[Zope] strange permission behaviour

Hi All! Ok, just in time for my new nervous-breakdown, read this: I have a ZClass which does have a "render" method. The render-method collects items from a catalog and calls these objects' "render" method. Unfortunately this raises an Unauthorised Error, whenever I do not use the super-user account. (Zope has encountered an error while publishing this resource. Unauthorized You are not authorized to access render. Ok, so I gave the calling Method the proxy-role of the Manager. No change. The strange thing about it is, and that is what puzzles me, that it works for another class (which does only slightly different things). So, what now, hu? Regards, Ingo.