Where is the lookup happening from? Is it a standalone Java program? If yes, are you including the jbossall-client.jar and the jar files referenced in its MANIFEST.MF, in your client classpath? Ensure that these jar files are the same as that on the server. If you are doing the lookup within the container (like from servlet or jsp), make sure that you are not packaging any jboss related jar files (like jbossall-client.jar) inside your application. Finally, if none of this helps you fix the issue, please post the output of the JNDI tree which you can view by following the steps mentioned here http://www.jboss.org/community/docs/DOC-9583 View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4186154#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...