I am getting the exact same behavior:
JBoss Oracle Patch 10G
JBoss version 4.0.2
Have you come to any resolution
Not sure if you guys are still interested in the solution but I just found the reason of the problem
you can easily fix the the problem by
a) unjar the "JBoss - Oracle AQ Patch 10g-mdb.jar"
b) edit jboss.xml and remove or comment the <mdb-user> and <mdb-passwd> tags.
it should fix the problem.