See http://wiki.jboss.org/wiki/Wiki.jsp?page=ClassLoadingConfiguration Also http://wiki.jboss.org/wiki/Wiki.jsp?page=JBossMessagingUser_Enabling_acce... may be useful depending on your deployment scenario. You don't need jboss-messaging-client.jar if everything is on the same machine. Just make sure your application ear is scoped and references the same classloading domain as JBM. Don't copy, add or overwrite any jars in the lib, server/messaging/lib or server/messaging/deploy directories. If you do, then you may break other apps or the app server which require there own versions of the lib. The installation script should do this all for you, apart from scoping your own EAR which you must do yourself. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4011819#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...