I had the similar problem. I was getting exact same exception on the server after switching from 4.0.4.GA to 4.2.2.GA. It turned out it was my fault, not JBoss'. I did not repackaged my client as I switched JBoss versions. My client was packaged with jbossall-client.jar from v4.0.4.GA while I was hitting v4.2.2.GA server. Make sure you recompile and repackage your client with appropriate version. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4121124#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...