ccoa's UMS shouldn't break like that...Are you sure everything is configured right?
Unfortunately, I can't help you anymore due to the whole lack of detail with everything. If there was a demo included with ccoa's UMS (There should be), then use that as reference to solving your problem.
If you don't want to use ccoa's UMS (I personally think it's one of the best Message systems out there), then there's many alternatives. Google gave me this one, for example.
http://www.hbgames.org/forums/viewtopic.php?t=4950