No, I'm not including any older classes, or jboss classes at all. I did check that. I also tried recompiling all the server and client code with the new jbossall-client.jar.
I'm starting the jboss server with just the run command, but as I said it seems to be running fine - no errors. My client application is a java application that connects to the application server via JNDI lookup. It has no web or browser component at all.