java.lang.IllegalStateException while using RTC Workspace

When I will unload, delete or load a component from a RTC Workspace or the workspace itself I get the following exception. How Can I delete/restore the workspace without any exception? The content of the workspace is not required anymore.

java.lang.IllegalStateException
    at com.ibm.team.internal.repository.rcp.dbhm.BTreeHeap.doFree(BTreeHeap.java:312)
    at com.ibm.team.internal.repository.rcp.dbhm.BTreeHeap.free(BTreeHeap.java:283)
    at com.ibm.team.filesystem.client.internal.PersistentHeapManager$AutoClosingPersistentFileHeap.free(PersistentHeapManager.java:128)
    at com.ibm.team.internal.repository.rcp.dbhm.DiskBackedHashMap.resizeIfNeeded(DiskBackedHashMap.java:440)
    at com.ibm.team.internal.repository.rcp.dbhm.DiskBackedHashMap.put(DiskBackedHashMap.java:168)
    at com.ibm.team.filesystem.client.internal.LockableMap$1.put(LockableMap.java:94)
    at com.ibm.team.filesystem.client.internal.core.MetadataChangeTracker.handleFileItemInfoSet(MetadataChangeTracker.java:787)
    at com.ibm.team.filesystem.client.internal.core.SharingMetadata2.setFileItemInfo(SharingMetadata2.java:2723)
    at com.ibm.team.filesystem.client.internal.copyfileareas.CopyFileAreaStore$7.visit(CopyFileAreaStore.java:2577)
    at com.ibm.team.filesystem.client.internal.core.SharingMetadata2.acceptAll(SharingMetadata2.java:1871)
    at com.ibm.team.filesystem.client.internal.core.SharingMetadata2.acceptAll(SharingMetadata2.java:1883)
    at com.ibm.team.filesystem.client.internal.core.SharingMetadata2.acceptAll(SharingMetadata2.java:1883)
    at com.ibm.team.filesystem.client.internal.core.SharingMetadata2.acceptAll(SharingMetadata2.java:1883)
    at com.ibm.team.filesystem.client.internal.core.SharingMetadata2.acceptAll(SharingMetadata2.java:1883)
    at com.ibm.team.filesystem.client.internal.core.SharingMetadata2.acceptAll(SharingMetadata2.java:1883)
    at com.ibm.team.filesystem.client.internal.core.SharingMetadata2.acceptAll(SharingMetadata2.java:1883)
    at com.ibm.team.filesystem.client.internal.core.SharingMetadata2.accept(SharingMetadata2.java:1845)
    at com.ibm.team.filesystem.client.internal.copyfileareas.CopyFileAreaStore.deleteTreeInfoInternal(CopyFileAreaStore.java:2551)
    at com.ibm.team.filesystem.client.internal.copyfileareas.CopyFileAreaStore.deleteTreeInfo(CopyFileAreaStore.java:2461)
    at com.ibm.team.filesystem.client.internal.copyfileareas.CopyFileArea.forget(CopyFileArea.java:117)
    at com.ibm.team.filesystem.client.internal.SharingManager.forget(SharingManager.java:544)
    at com.ibm.team.filesystem.client.internal.Shareable.unshare(Shareable.java:389)
    at com.ibm.team.filesystem.client.internal.share.UnshareOperation$1.run(UnshareOperation.java:170)
    at com.ibm.team.filesystem.rcp.core.internal.resources.ResourceSharingManager$1.run(ResourceSharingManager.java:76)
    at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2344)
    at com.ibm.team.filesystem.rcp.core.internal.resources.ResourceSharingManager.runWithinFileSystemLock(ResourceSharingManager.java:88)
    at com.ibm.team.filesystem.client.internal.operations.FileSystemOperation.runWithinFileSystemLock(FileSystemOperation.java:164)
    at com.ibm.team.filesystem.client.internal.operations.FileSystemOperation.runWithinFileSystemLock(FileSystemOperation.java:144)
    at com.ibm.team.filesystem.client.internal.share.UnshareOperation.execute(UnshareOperation.java:260)
    at com.ibm.team.filesystem.client.internal.operations.FileSystemOperation.run(FileSystemOperation.java:89)
    at com.ibm.team.internal.filesystem.ui.actions.components.UnloadConfigurationDescriptorAction$1.repositoryRun(UnloadConfigurationDescriptorAction.java:77)
    at com.ibm.team.repository.rcp.ui.operations.RepositoryOperation.run(RepositoryOperation.java:43)
    at com.ibm.team.repository.rcp.ui.operations.JobRunner.run(JobRunner.java:240)
    at com.ibm.team.repository.rcp.ui.operations.JobRunner$1.run(JobRunner.java:63)
    at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)