[Zope] migration from 2.1.6 -> 2.2.0 breaks ZClass

[Ramalingam, Padmanaba [Padhu] [VIS-Non J&J]]

Hi,

	I have migrated from 2.1.6 to 2.2.0 by copying Data.fs. Everything
works except when I try to create 
a new ZClass, I get "Could not load oid" error. Any help how to fix it is
appreciated.

Thanks,
Padhu

Traceback (innermost last):
  File E:\2gtzope\lib\python\ZPublisher\Publish.py, line 222, in
publish_module
  File E:\2gtzope\lib\python\ZPublisher\Publish.py, line 187, in publish
  File E:\2gtzope\lib\python\Zope\__init__.py, line 221, in
zpublisher_exception_hook
    (Object: ElementWithAttributes)
  File E:\2gtzope\lib\python\ZPublisher\Publish.py, line 171, in publish
  File E:\2gtzope\lib\python\ZPublisher\mapply.py, line 160, in mapply
    (Object: manage_addZClass)
  File E:\2gtzope\lib\python\ZPublisher\Publish.py, line 112, in call_object
    (Object: manage_addZClass)
  File E:\2gtzope\lib\python\ZClasses\ZClass.py, line 154, in
manage_addZClass
    (Object: ElementWithAttributes)
  File E:\2gtzope\lib\python\OFS\ObjectManager.py, line 260, in _setObject
    (Object: ElementWithAttributes)
  File E:\2gtzope\lib\python\ZClasses\ZClass.py, line 421, in
manage_afterAdd
    (Object: CDClass)
  File E:\2gtzope\lib\python\ZClasses\ZClass.py, line 374, in _register
    (Object: CDClass)
  File E:\2gtzope\lib\python\ZODB\Connection.py, line 447, in setstate
  File E:\2gtzope\lib\python\ZODB\Connection.py, line 213, in
_persistent_load
    (Info:       m)
  File E:\2gtzope\lib\python\ZODB\Connection.py, line 154, in __getitem__
    (Info: ('\000\000\000\000\000\000\005m', 
<------------------snip--------------->
Could not load oid       m, pickled data in traceback info may
contain clues: (see above)