You haven't provided very much info, but here's a couple of things you need to verify.
1) Are you using the latest IBM jdk filesets?
2) Did you build Jboss-3.2.7 using the IBM 1.3.1 JDK? (I'd recommend you do so)
You definitely can't just deploy the binary distribution of Jboss on JDK-1.3.1 since it was built with JDK-1.4.