Java API throws IllegalArgumentException

I am using RTC version 3.0, and accessing JAVA api.

I am facing the following problem while trying to fetch the enumerations:

Code snippet:
IEnumeration<IPriority> enums = (IEnumeration<IPriority>)workItemClient.resolveEnumeration(attribute, null);


Also, the same error occurs, while doing following operation:
IWorkItemType workItemType = service.findWorkItemType(projectArea, "defect", new SysoutProgressMonitor());



Exception in thread "main" java.lang.IllegalArgumentException
at com.ibm.team.process.internal.common.util.AbstractProcess.computeConfigurationData(AbstractProcess.java:328)
at com.ibm.team.process.internal.common.util.AbstractProcess.getProjectConfigurationData(AbstractProcess.java:313)
at com.ibm.team.process.internal.common.util.AbstractProcess.getProjectConfigurationData(AbstractProcess.java:299)
at com.ibm.team.workitem.client.internal.AuditableClientProcess.findProcessConfiguration(AuditableClientProcess.java:68)
at com.ibm.team.workitem.common.internal.EnumerationManager$InternalEnumerations.resolve(EnumerationManager.java:52)
at com.ibm.team.workitem.common.internal.EnumerationManager.updateCache(EnumerationManager.java:198)
at com.ibm.team.workitem.common.internal.util.CacheHelper.internalCheckCache(CacheHelper.java:117)
at com.ibm.team.workitem.common.internal.util.CacheHelper.checkCache(CacheHelper.java:74)
at com.ibm.team.workitem.common.internal.util.CacheHelper.checkCache(CacheHelper.java:65)
at com.ibm.team.workitem.common.internal.EnumerationManager.internalResolve(EnumerationManager.java:173)
at com.ibm.team.workitem.common.internal.EnumerationManager.resolve(EnumerationManager.java:169)
at com.ibm.team.workitem.common.internal.WorkItemCommon.resolveEnumeration(WorkItemCommon.java:453)
at CreateWorkItem.main(CreateWorkItem.java:147)