Plone Import Problem....

I had a site up on Zettai with the previous version of Plone 2.7.   I'm 
moving it to a new site with the newer 2.9 version

I exported each folder separately so as to not miss anything.  I 
exported the skins custom folder, etc.

The objects/folders import

I can open some of them (not folders) and I'm getting various errors 
having to do with Attributes and Schemata.

See below...

Site error

This site encountered an error trying to fulfill your request. The 
errors were:

Error Type
     AttributeError
Error Value
     Schemata

In another case, I go into the folder in the management interface, look 
at it's index_html, view it and I can view it.

But when I click on the Nav tree for that folder, I get this...

  This site encountered an error trying to fulfill your request. The 
errors were:

Error Type
     RuntimeError
Error Value
     maximum recursion depth exceeded in cmp

Any ideas?