I upgraded to Zope2.0b5, added a product and then attempted to add a ZClass to that product, but I get the error shown below. I went back to beta 3 and did the same thing with success. Both Zope's were compiled from source in the same way. Has something happened to ZClasses? I can add anything else to a new product fine, just not a ZClass. Thanks in advance for any help, Jason Jones jason_j@countermedia.org Traceback (innermost last): File /web/zope2b5/lib/python/ZPublisher/Publish.py, line 209, in publish_module File /web/zope2b5/lib/python/ZPublisher/Publish.py, line 179, in publish File /web/zope2b5/lib/python/Zope/__init__.py, line 199, in zpublisher_exception_hook (Object: ElementWithAttributes) File /web/zope2b5/lib/python/ZPublisher/Publish.py, line 165, in publish File /web/zope2b5/lib/python/ZPublisher/mapply.py, line 154, in mapply (Object: manage_addZClassForm) File /web/zope2b5/lib/python/ZPublisher/Publish.py, line 102, in call_object (Object: manage_addZClassForm) File /web/zope2b5/lib/python/App/special_dtml.py, line 120, in __call__ (Object: manage_addZClassForm) (Info: /web/zope2b5/lib/python/ZClasses/addZClass.dtml) File /web/zope2b5/lib/python/DocumentTemplate/DT_String.py, line 502, in __call__ (Object: manage_addZClassForm) File /web/zope2b5/lib/python/DocumentTemplate/DT_With.py, line 148, in render (Object: _(selected=[], unselected=[], baseclasses=[], id='', title='', meta_type='', all=manage_subclassableClassNames(), )) File /web/zope2b5/lib/python/DocumentTemplate/DT_With.py, line 148, in render (Object: REQUEST) File /web/zope2b5/lib/python/DocumentTemplate/DT_With.py, line 148, in render (Object: _( selected=_.reorder( all, with = baseclasses+ (REQUEST.get('manage_addZClassForm','')==' -> ' and unselected or []), without= (REQUEST.get('manage_addZClassForm','')==' <- ' and selected or []) ), )) File /web/zope2b5/lib/python/DocumentTemplate/DT_With.py, line 148, in render (Object: _(unselected=_.reorder(all, without=selected))) File /web/zope2b5/lib/python/DocumentTemplate/DT_In.py, line 689, in renderwob (Object: unselected) TypeError: (see above)