Getting Exception from the client code while retrieving the Crowd Groups

Hi,
I am getting below exception from the Java client code which is written to fetch the Groups exists in the crowd.

Exception in thread "main" java.lang.NoClassDefFoundError
at org.codehaus.xfire.aegis.type.DefaultTypeMappingRegistry.class$(DefaultTypeMappingRegistry.java:64)
at org.codehaus.xfire.aegis.type.DefaultTypeMappingRegistry.createDefaultMappings(DefaultTypeMappingRegistry.java:399)
at org.codehaus.xfire.aegis.type.DefaultTypeMappingRegistry.createDefaultMappings(DefaultTypeMappingRegistry.java:304)
at org.codehaus.xfire.aegis.type.DefaultTypeMappingRegistry.<init>(DefaultTypeMappingRegistry.java:130)
at org.codehaus.xfire.aegis.type.DefaultTypeMappingRegistry.<init>(DefaultTypeMappingRegistry.java:118)
at org.codehaus.xfire.aegis.AegisBindingProvider.<init>(AegisBindingProvider.java:66)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at org.codehaus.xfire.service.binding.ObjectServiceFactory.getBindingProvider(ObjectServiceFactory.java:161)
at org.codehaus.xfire.service.binding.DefaultServiceConfiguration.getInParameterName(DefaultServiceConfiguration.java:160)
at org.codehaus.xfire.service.binding.ObjectServiceFactory.getInParameterName(ObjectServiceFactory.java:1044)
at org.codehaus.xfire.service.binding.ObjectServiceFactory.addOperation(ObjectServiceFactory.java:798)
at org.codehaus.xfire.service.binding.ObjectServiceFactory.initializeOperations(ObjectServiceFactory.java:742)
at org.codehaus.xfire.service.binding.ObjectServiceFactory.create(ObjectServiceFactory.java:426)
at com.atlassian.crowd.integration.service.soap.client.SecurityServerClientImpl.getSecurityServer(SecurityServerClientImpl.java:69)
at com.atlassian.crowd.integration.service.soap.client.SecurityServerClientImpl.searchGroups(SecurityServerClientImpl.java:279)

Please let me know if you require any details