problem of deleting archive while content is archived

2011-11-08 09:58:04,919 ERROR [org.ametys.cms.observation.ObservationManager] (5678233@qtp-12700959-3;/cms/plugins/core/servercomm/messages.xml) Unable to dispatch event: event[content.deleted, org.ametys.web.repository.content.jcr.DefaultWebContent@9d4bf73c] to observers
java.lang.ClassCastException: org.ametys.web.repository.content.jcr.DefaultWebContent cannot be cast to java.lang.String
at org.ametys.web.synchronization.SynchronizeContentDeletionObserver._internalObserve(SynchronizeContentDeletionObserver.java:85)
at org.ametys.web.synchronization.AbstractSynchronizeObserver.observe(AbstractSynchronizeObserver.java:87)
at org.ametys.cms.observation.ObservationManager.notify(ObservationManager.java:95)
at org.ametys.cms.workflow.ArchiveContentAction._act(ArchiveContentAction.java:93)
at org.ametys.plugins.workflow.cocoon.AbstractWorkflowAction.act(AbstractWorkflowAction.java:58)
at org.apache.cocoon.components.treeprocessor.sitemap.ActTypeNode.invoke(ActTypeNode.java:125)
at org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invokeNodes(AbstractParentProcessingNode.java:47)
at org.apache.cocoon.components.treeprocessor.sitemap.ActTypeNode.invoke(ActTypeNode.java:139)