I don't know very much about your concrete setup. Are you using a remote client, using the remote interface via RMI to call some method? We experience similar problems, when the client is not exactly the same version as the server. This may mean, the client uses out-dated interfaces to call methods on. These can not be found at the server, as the method hash is different. Our experience with the problem shows, that this may even happen if the method did not change. Hope this is of help to you. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4219994#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...