[Zope] ZODB bug? (Surrogate instance '_p_oid')

Hello everybody. Can somebody explain what this error means? I think this sounds like a bug in ZODB somewhere... :( Zope: 2.6.1 OS: Linux SuSE 8.0 Pro ============================================== Traceback (innermost last): * Module ZPublisher.Publish, line 102, in publish * Module Zope.App.startup, line 200, in commit * Module ZODB.Transaction, line 261, in commit * Module ZODB.Transaction, line 392, in _commit_error AttributeError: Surrogate instance has no attribute '_p_oid' ============================================== -- Regards, Bogdan If nothing else helps, read the documentation.