I think there are two possibilities:
1. You finde the one that does develop your applications and ask him.
2. You change the logging level and hope that under a more talkful level you will get the information you need. You can change the logging level under jboss/server//conf/log4j.xml. There you can change the logging level for the logger and category you want to something useful (DEBUG, for example).
ok does it do a thread dump?
i don't know how to put in place a thread dump when it crashes.
I didn't set up log4j.xml, i will do it very soon i hope.
Actually since i came into the forum, the apps is stable (for now...)