Thank you for the reply! Since posting the question, I thought it might help to try the latest stable release of JBoss, so I upgraded from 4.0.4GA to 4.0.5GA and added the messaging as I did on 4.0.4GA. All messaging examples run fine so I deployed my app and it worked! I didn't experience any problem I had when I adding messaging with 4.0.4GA, such as "Not a JBossQueue" exception due to classloader resolution. I still have the 4.0.4GA on my disk, so I'll run it again with leasePeriod=0 and will post back the result on this thread. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4010283#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...