[Zope] Problems upgrading - broken ZClass instances

[Itamar Shtull-Trauring]

I'm moving machines and upgrading Zope, so I moved the old Data.fs* from
machine A (zope 2.0.1) and moved them into an installation of 2.1.0b1 on
machine B.  As a result, all my ZClass instances are now broken - the say:
	 
       recipes (This object from the unknown product is broken!) 

and I'm getting errors on startup such as 

	ImportError: No module named *5imovKZn6trBy2xCM8ycbg==
	------
	1999-11-07T08:26:06 ERROR(200) ZODB Couldn't load state for
'\000\000\000\000\000\000\000\002'

and in fact none of my ZClasses have that value.

Any ideas?