Patch MultiHook for downgrades from Zope 2.5 to Zope 2.4/2.3. Zope 2.5 inserts an instance of SessionTraverser as a before publishing traverse function into the Application object's root. When Zope 2.4 attempts to use this as a before publishing traverse method, an error is raised because the MultiHook is actually trying to call a broken object (because there is no such class SessionTraverser in Zope 2.4, and Zope inserts "broken" objects for persistent objects that it can't find on the filesystem). As broken objects have no __call__ method, the symptom shows itself as an 'AttributeError: __call__ in line 171 of BeforeTraverse.py.

This patch causes the error to be logged but not raised to the application layer.

Install this like any other Product and restart your Zope.