GIMSPOP writes:
... The test I have done is to install two "fresh" Zopes (same Zope, same CMF, no other add-ons) on the same machine. Instance home the one Zope, leave the other one as is. Create a new CMF site from scratch in Zope1. Export it from Zope1, import it into Zope2. (I also did this the other way around). In both cases, the import shows broken Portal Folder icons and the site does not render. Only in my production site's case do I get the traceback. The fresh install test also does not work - it doesn't show a traceback, but just doesn't render - instead I get the standard Zope intro page. As if the portal does not have a default document. I am sure, I answered a similar question recently.
Did you check the properties in the "DirectoryView" folders (located in "portal_skins --> Content"). I guess, some of them are too short in the non-INSTANCE_HOME Zope site. Dieter