Error while trying to import users and groups

When I tried to import users and groups I received the following error -

System Error

A system error has occurred please contact your administrator.
If this problem continues to occur please contact Atlassian by opening a support request with the following information:

• A description of your problem and what you were doing at the time it occurred
• Cut & paste the error and system information found below
• Attach the application server log file (if possible).
  Cause :
  java.lang.NullPointerException
  Stack Trace :
  java.lang.NullPointerException
  at com.atlassian.crowd.importer.importers.BaseImporter.mapContainersToChildren(BaseImporter.java:128)
  at com.atlassian.crowd.importer.importers.BaseImporter.importUserMemberships(BaseImporter.java:147)
  at com.atlassian.crowd.importer.importers.BaseImporter.importUserToGroupMemberships(BaseImporter.java:266)
  at com.atlassian.crowd.importer.importers.BaseImporter.importUsersGroupsAndMemberships(BaseImporter.java:248)
  at com.atlassian.crowd.importer.importers.CsvImporter.importUsersGroupsAndMemberships(CsvImporter.java:27)
  at com.atlassian.crowd.importer.manager.ImporterManagerImpl.performImport(ImporterManagerImpl.java:36)
  at com.atlassian.crowd.console.action.dataimport.CsvConfirmation.doExecute(CsvConfirmation.java:38)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
  at java.lang.reflect.Method.invoke(Method.java:597)
  at com.opensymphony.xwork.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:358)
  at com.opensymphony.xwork.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:218)
  at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:192)
  at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
  at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
  at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
  at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
  at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
  at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
  at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
  at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
  at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
  at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
  at com.atlassian.xwork.interceptors.TransactionalInvocation.invokeAndHandleExceptions(TransactionalInvocation.java:72)
  at com.atlassian.xwork.interceptors.TransactionalInvocation.invokeInTransaction(TransactionalInvocation.java:59)
  at com.atlassian.xwork.interceptors.XWorkTransactionInterceptor.intercept(XWorkTransactionInterceptor.java:56)
  at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
  at com.opensymphony.xwork.DefaultActionProxy.execute(DefaultActionProxy.java:116)
  at com.opensymphony.webwork.dispatcher.DispatcherUtils.serviceAction(DispatcherUtils.java:273)
  at com.opensymphony.webwork.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:202)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:118)
  at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:52)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
  at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
  at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.opensymphony.webwork.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:88)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
  at org.springframework.security.intercept.web.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
  at org.springframework.security.intercept.web.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
  at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
  at org.springframework.security.ui.ExceptionTranslationFilter.doFilterHttp(ExceptionTranslationFilter.java:101)
  at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
  at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
  at org.springframework.security.providers.anonymous.AnonymousProcessingFilter.doFilterHttp(AnonymousProcessingFilter.java:105)
  at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
  at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
  at org.springframework.security.wrapper.SecurityContextHolderAwareRequestFilter.doFilterHttp(SecurityContextHolderAwareRequestFilter.java:91)
  at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
  at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
  at org.springframework.security.ui.AbstractProcessingFilter.doFilterHttp(AbstractProcessingFilter.java:277)
  at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
  at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
  at org.springframework.security.ui.logout.LogoutFilter.doFilterHttp(LogoutFilter.java:89)
  at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
  at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
  at org.springframework.security.context.HttpSessionContextIntegrationFilter.doFilterHttp(HttpSessionContextIntegrationFilter.java:235)
  at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
  at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
  at org.springframework.security.util.FilterChainProxy.doFilter(FilterChainProxy.java:175)
  at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:236)
  at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
  at com.atlassian.crowd.console.filter.CrowdDelegatingFilterProxy.doFilter(CrowdDelegatingFilterProxy.java:38)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
  at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
  at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.atlassian.crowd.console.filter.LicenceFilter.doFilterInternal(LicenceFilter.java:54)
  at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
  at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:236)
  at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
  at com.atlassian.crowd.console.filter.CrowdDelegatingFilterProxy.doFilter(CrowdDelegatingFilterProxy.java:38)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.atlassian.johnson.filters.AbstractJohnsonFilter.doFilter(AbstractJohnsonFilter.java:71)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:70)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
  at com.atlassian.crowd.console.filter.CrowdOpenSessionInViewFilter.doFilterInternal(CrowdOpenSessionInViewFilter.java:26)
  at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.atlassian.crowd.plugin.web.filter.RequestCacheThreadLocalFilter.doFilter(RequestCacheThreadLocalFilter.java:31)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.atlassian.gzipfilter.GzipFilter.doFilterInternal(GzipFilter.java:75)
  at com.atlassian.gzipfilter.GzipFilter.doFilter(GzipFilter.java:51)
  at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:236)
  at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
  at com.atlassian.crowd.console.filter.CrowdDelegatingFilterProxy.doFilter(CrowdDelegatingFilterProxy.java:38)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
  at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
  at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.atlassian.core.filters.cache.AbstractCachingFilter.doFilter(AbstractCachingFilter.java:33)
  at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.atlassian.core.filters.encoding.AbstractEncodingFilter.doFilter(AbstractEncodingFilter.java:41)
  at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at com.atlassian.core.filters.encoding.AbstractEncodingFilter.doFilter(AbstractEncodingFilter.java:41)
  at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
  at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
  at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
  at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
  at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
  at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
  at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190)
  at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:291)
  at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:776)
  at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:705)
  at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:898)
  at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:690)
  at java.lang.Thread.run(Thread.java:662)
  Referer : https://icustomer.dsthealthsolutions.com/crowd/console/secure/dataimport/csvconfirm!default.action
  Build Information :
  Version : 2.2.4 (Build:#490 - 29-03-2011)
  Memory Information :
  Total Memory : 164 MB
  Free Memory : 27 MB
  Used Memory : 137 MB
  Request Information :
• Request URL : https://icustomer.dsthealthsolutions.com/crowd/console/500.jsp
• Scheme : https
• Server : icustomer.dsthealthsolutions.com
• Port : 443
• URI : /crowd/console/500.jsp
• Context Path : /crowd
• - Servlet Path : /console/500.jsp
• - Path Info : null
• - Query String :

Request Attributes :

• javax.servlet.forward.request_uri : /crowd/console/secure/dataimport/csvconfirm!doExecute.action
• javax.servlet.forward.context_path : /crowd
• javax.servlet.forward.servlet_path : /console/secure/dataimport/csvconfirm!doExecute.action
• javax.servlet.forward.path_info : /console/500.jsp
• javax.servlet.error.status_code : 500
• javax.servlet.error.servlet_name : default
• javax.servlet.request.key_size : 256
• com.atlassian.gzipfilter.GzipFilter_already_filtered : true
• __cleanup_counter : 0
• com.atlassian.johnson.filters.JohnsonFilter_already_filtered : true
• gzipMimeTypes : text/.*,application/x-javascript,application/javascript,application/xml,application/xhtml+xml
• com.atlassian.crowd.integration.http.HttpAuthenticator.REQUEST_SSO_COOKIE_COMMITTED : true
• javax.servlet.request.ssl_session : E801D6AB5F6CB79E5BA998EA51BE1359676C14DEC0F7A935E537EB67C79539F2
• javax.servlet.error.message :
• com.atlassian.gzipfilter.org.tuckey.web.filters.urlrewrite.RuleMatched : true
• webwork.valueStack : com.opensymphony.xwork.util.OgnlValueStack@23e6c353
• _sitemesh_filterapplied : true
• javax.servlet.request.cipher_suite : DHE-RSA-AES256-SHA
• javax.servlet.error.exception : javax.servlet.ServletException: java.lang.NullPointerException
• __spring_security_filterSecurityInterceptor_filterApplied : true
• javax.servlet.error.request_uri : /crowd/console/secure/dataimport/csvconfirm!doExecute.action
• crowd.token_key : 9BNvO1xg9dsxgO8pWnfH2A00

Request Parameters: