Hi James,
I vaguely remember a classloading problem in AS being found and fixed, but I don't remember what the problem was. The main reason I became aware of it was that it looked, at first, like a Remoting problem. So, in the absence of any concrete information, I'll make three suggestions.
1. Pose the question on the AS forum (http://community.jboss.org/en/jbossas), or
2. try building AS from trunk (http://anonsvn.jboss.org/repos/jbossas/trunk/, or
3.wait for M3, which isn't too far away.
Glad you're still with us!
-Ron