We had this issue. We had two instances of jboss in cluster and were getting these messages in log. It was because we had two implementations of JGroups with different version located in server/default/lib. Occasionally each of servers in cluster were choosing its own implementation so they were incompatible: 2.2.8 and 2.2.7.1. The removal of redundant jar resolved the issue. In your case it seems that your JBoss is conflicting with another one in the same network. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4211269#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...