Well, it could be worse. It could be not working and keeping that quiet.
Which database are you using here?
I am running into the same error. I can create the CMP objects, but accessing them afterwards, or accessing an object returned by a find method, causes the same error.
I'm running JBoss 3.0.0 w/ Jetty, and my backend is MySQL 3.23.49a.
I had the same problem.
It turns out that the transaction manager is getting confused .
Try removing all of your XDoclet transaction tags -- that fixed it for me.