Can you post a few more lines of the stack trace?
This looks like you have a bad container configuration. Are you upgrading an application or messed with the jboss.xml file? If so, make sure you have all of the correct interceptors and such from the new JBoss 3.0 standardjboss.xml file. I assume you are using JBoss 3.0 (rc1) as you are talking about relationships.
The problem was just on the stubs,
when I made a .jar, it tryied to get old classes instead of the most recent ones. So, the conf. its ok, and my problem too, anyway, thanks for your advice!