I'm having a similar problem, I am coming with a war that works in jboss5 and trying to deploy it to jboss6 and am receiving the error
I beleive its because the war has packaged with it a 2.1 version of jaxb-xjc.jar:
Caused by: java.lang.Error: Error visiting "/C:/***.war/WEB-INF/lib/jaxb-xjc.jar/1.0/com/sun/codemodel/JConditional.class"
I am not limited by anything I can do on the server or the app.
I have tried to replace the jaxb-xjc.jar (v2.1) in my app to the jBoss default of (2.2) - fail
I have tried to delete the .jar from both the war and the jboss/lib folder but it gives me the exact same error.
Any guidance on how to quickly and easily fix this would be much appreciated