The verifier in 3.0 is still a work in progress. Verifiers are always the last thing written.
It looks like the verifier is saying that you have a custom primary key, yet you still have a prim-key-field declaration in your ejb-jar.xml file. If you have a custom primary key class you do not need a prim-key-field declaration (actually, I don't think you are allowed to have the field declaration).
Either way, this is a very ugly error message, so you should post a bug report at sourceforge, and the guy who maintains the verifier will fix it.
Thanks for the quick response.
i do have a <primkey-field/> entry in my ejb-jar.xml file.
the exception went away after i remove the entry.
i think the error massages are fine, but the program should be more forgiving as <primkey-field/> means the same as not having such an entry. because it is an empty element anyway.