Hi i had similar exception and i could not solve this exception. I got this exception after i added some jars to my jboss-AS-4.0.5/server/default/'lib directory (also i replaced some existing jars by mistake). I could not find a solution to this problem. I also posted this problem. http://www.jboss.com/index.html?module=bb&op=viewtopic&t=116697 I did not find any reply. so finally i checked out jboss portal 2.6.1 again , build it and deployed. Id did not throw any exception after that. (this time i was careful while adding jars to default/lib) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4078581#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...