Upgrade from CONF 1.4.4 to 2.1.3 and restore of site backup leads to curious page states in some spaces

I upgraded to Version 2.1.3 and restored the backup of the site. Most things are OK.
But:
the customized "Main Layout" is now bad for the space list and some spaces have wrong

-Lists of their child pages. Some pages seems to be not existing. The validation in "browse space" shows that they are here. You can view and edit them. But you can also add them second and twice with the same page title. After added them twice, you can no longer call the listpages-alphaview action. An error is coming up:

java.lang.ClassCastException: java.util.Date
at java.sql.Timestamp.compareTo(Timestamp.java:474)
at com.atlassian.confluence.core.ContentEntityObject.compareTo(ContentEntityObject.java:269)
at java.util.Arrays.mergeSort(Arrays.java:1156)
at java.util.Arrays.sort(Arrays.java:1080)
at java.util.Collections.sort(Collections.java:117)
at com.atlassian.confluence.pages.actions.AlphabeticalListPagesAction.getItems(AlphabeticalListPagesAction.java:36)
at com.atlassian.confluence.pages.actions.AbstractPaginatedListAction.execute(AbstractPaginatedListAction.java:22)
at com.atlassian.confluence.pages.actions.AlphabeticalListPagesAction.execute(AlphabeticalListPagesAction.java:20)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:168)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.opensymphony.xwork.interceptor.DefaultWorkflowInterceptor.intercept(DefaultWorkflowInterceptor.java:55)
at com.atlassian.confluence.core.ConfluenceWorkflowInterceptor.intercept(ConfluenceWorkflowInterceptor.java:38)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
at com.atlassian.confluence.core.ConfluenceValidationInterceptor.intercept(ConfluenceValidationInterceptor.java:16)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.atlassian.confluence.security.actions.PermissionCheckInterceptor.intercept(PermissionCheckInterceptor.java:39)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.atlassian.confluence.pages.actions.PageAwareInterceptor.intercept(PageAwareInterceptor.java:94)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.atlassian.confluence.spaces.actions.SpaceAwareInterceptor.intercept(SpaceAwareInterceptor.java:82)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.atlassian.confluence.core.ConfluenceAutowireInterceptor.intercept(ConfluenceAutowireInterceptor.java:25)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.atlassian.confluence.util.XWorkTransactionInterceptor.intercept(XWorkTransactionInterceptor.java:133)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.opensymphony.xwork.DefaultActionProxy.execute(DefaultActionProxy.java:115)
at com.opensymphony.webwork.dispatcher.ServletDispatcher.serviceAction(ServletDispatcher.java:229)
at com.opensymphony.webwork.dispatcher.ServletDispatcher.service(ServletDispatcher.java:199)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:118)
at com.atlassian.confluence.util.profiling.ProfilingPageFilter.parsePage(ProfilingPageFilter.java:150)
at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.confluence.util.ServletContextThreadLocalFilter.doFilter(ServletContextThreadLocalFilter.java:30)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.confluence.util.UserThreadLocalFilter.doFilter(UserThreadLocalFilter.java:45)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:182)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.seraph.filter.LoginFilter.doFilter(LoginFilter.java:177)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.johnson.filters.JohnsonFilter.doFilter(JohnsonFilter.java:96)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.springframework.orm.hibernate.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:170)
at bucket.custom.FlushingSpringSessionInViewFilter.doFilterInternal(FlushingSpringSessionInViewFilter.java:31)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:73)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.util.profiling.filters.ProfilingFilter.doFilter(ProfilingFilter.java:132)
at com.atlassian.confluence.util.error.ProfilingAndErrorFilter.doFilter(ProfilingAndErrorFilter.java:27)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.core.filters.gzip.GzipFilter.doFilter(GzipFilter.java:61)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.core.filters.AbstractEncodingFilter.doFilter(AbstractEncodingFilter.java:37)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:81)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.jboss.web.tomcat.security.CustomPrincipalValve.invoke(CustomPrincipalValve.java:39)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:153)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:59)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:744)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
at java.lang.Thread.run(Thread.java:595)

Referer URL: http://pcx09802.ops.oce.net:8080/confluence/spaces/spaceadmin.action?key=0003

Build Information:
Confluence Home: /opt/jboss-4.0.2p/server/default/data/confluence
Uptime: 1 hour, 31 minutes, 4 seconds
Version: 2.1.3
Build Number: 408

Server Information:
Application Server: Apache Tomcat/5.5.9
Servlet Version: 2.4
Database Dialect: bucket.dialect.MySQLDialect
Database Driver Name: N/A
Database Driver Version: N/A

Memory Information:
Total Memory: 506 MB
Free Memory: 411 MB
Used Memory: 95 MB

System Information:
System Date: Freitag, 27 Jan 2006
System Time: 19:48:57
System Favourite Colour: Chartreuse
Java Version: 1.5.0_05
Java Vendor: Sun Microsystems Inc.
JVM Version: 1.0
JVM Vendor: Sun Microsystems Inc.
JVM Implementation Version: 1.5.0_05-b05
Java Runtime: Java(TM) 2 Runtime Environment, Standard Edition
Java VM: Java HotSpot(TM) Server VM
User Name: jboss
User Timezone: Europe/Berlin
Operating System: Linux 2.6.11.4-21.9-default
OS Architecture: i386
Filesystem Encoding: UTF-8
Request

Information:
URL: http://pcx09802.ops.oce.net:8080/confluence/500page.jsp

• Scheme: http
• Server: pcx09802.ops.oce.net
• Port: 8080
• URI: /confluence/500page.jsp
• - Context Path: /confluence
• - Servlet Path: /500page.jsp
• - Path Info: null
• - Query String: key=0003

Attributes:

• javax.servlet.forward.request_uri : /confluence/pages/listpages-alphaview.action
• javax.servlet.forward.context_path : /confluence
• javax.servlet.forward.servlet_path : /pages/listpages-alphaview.action
• javax.servlet.forward.path_info : /500page.jsp
• javax.servlet.forward.query_string : key=0003
• javax.servlet.error.message :
• javax.servlet.error.exception : java.lang.ClassCastException: java.util.Date
• os_securityfilter_already_filtered : true
• _sitemesh_using_stream : false
• com.atlassian.johnson.filters.JohnsonFilter_already_filtered : true
• javax.servlet.error.request_uri : /confluence/pages/listpages-alphaview.action
• javax.servlet.error.status_code : 500
• _sitemesh_filterapplied : true
• javax.servlet.error.servlet_name : action
• webwork.valueStack : com.opensymphony.xwork.util.OgnlValueStack@2b9ca
• atlassian.core.seraph.original.url : /pages/listpages-alphaview.action?key=0003
• loginfilter.already.filtered : true
• javax.servlet.jsp.jspException : java.lang.ClassCastException: java.util.Date
• sessioninview.FILTERED : true
• com.atlassian.core.filters.gzip.GzipFilter_already_filtered : true

Parameters:

• key = 0003

Logging:
0 log statements generated by this request.