Ok, just to be sure, here are the steps I have followed: 1) Installed JBoss 4.0.4.GA-Patch1 using the installer jar 2) Unzipped jboss-messaging-1.0.1.CR3.zip and run the release-admin.xml ant script. 3) Copied the jboss-messaging-client.jar into my standalone client's lib directory (all that is in there beyond that is log4j.xml) 4) Set the classpath of my client to use only what is in the lib directory mentioned in step 3. 5) Started my JBoss server (the destinations deploy) 6) Run my client. I still get the same errors. I've tried this 4 times now, adjusting libraries here and there, and I'm still having no luck. Is it possible that the jboss-messaging-client.jar that comes with jboss-messaging-1.0.1.CR3.zip is incompatible? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3957838#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...