I made some experiments and found, that removing from the generated XML file all tags named <klass>, <state> and <object> (together with their contents) changes something - loading takes longer and is finished with different error: Error Type: AttributeError Error Value: 'string' object has no attribute '__dict__' I can not find word __dict__ anywhere in my xml file, maybe some of Base64 encoded object contain such a thing... My main suspicion is that I have problem with importing ZCatalog objects -- Marcin.Kasperski | As a slow-witted human being I have a very small head @softax.com.pl | and I had better learn to live with it and to respect Marcin.Kasperski | my limitations, rather than to try to ignore them. @bigfoot.com | (Dijskstra)