Thanks for help. My project come from previous eclipse (3.1). When I start the server in debug mode in JBoss AS perspective(JBoss Server view). Then go the Java perspective and package the application into ear. Then right click on this ear, from popup menu Run As --> Run on Server, there is a Server Error popup window with the message as: The selection is not within a valid module. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4007012#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...