[Zope] not safe for unpickling

I am getting this error on a site and I would like to find what objects or object types are causing it so that I can fix the problem. Functions should not be pickled and I am not sure how someone did get some pickled. It was originally a zope 2.3.3 installation that was upgraded. 2001-12-11T17:59:19 ERROR(200) ZODB Couldn't load state for '\x00\x00\x00\x00\x00\x00E\x94' Traceback (innermost last): File /home/zope/Zope-2.4.3-linux2-x86/lib/python/ZODB/Connection.py, line 544, in setstate UnpicklingError: <function HTML at 0x8615e14> is not safe for unpickling Designing the webpages of tomorrow http://webme-eng.com Designing the MMORPGS of tomorrow http://worldforge.org