Mr Stansberry, We're using sticky sessions, we understand how to configure them and as far as I know they are working correctly, but we are still seeing the "Possible concurrency problem" message." To elaborate a little on our configuration, we use jBoss4.0.5GA with Apache 2.2.4 on the front end using mod_proxy_ajp for load balancing. There are actually 2 issues we are seeing: 1) The "Possible Concurrency Problem" message. We are using REPL_ASYNC and REPEATABLE_READ in the tc5 cluster setup. I should note that we used the same setup in our last environment which was 4.0.2 and everything worked fine. 2) Although we have mod_proxy_ajp setup to use sticky sessions, it doesnt appear to be doing that, hence the discovery of #1 above b/c we get NPEs accessing session attributes as mod_proxy distributes requests across multiple JBoss instances and the session attributes arent being replicated properly. I think a solution to either of these 2 problems helps out everyone, although I recognize #2 is probably not within the scope of this thread. I think regardless of StickySession (which I fully understand), there is an issue with Session replication. Hope this helps and we appreciate your time and attention to this forum. Thank you. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4044486#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...