[Zope] Can't Undo any transactions in Zope 2.7!

I can't undo ANY transactions in 2.7 (python 2.3.3). Anyone else having the same problems or know solutions? Here is traceback: Traceback (innermost last): Module ZPublisher.Publish, line 104, in publish Module Zope.App.startup, line 221, in commit Module ZODB.Transaction, line 233, in commit Module ZODB.Transaction, line 348, in _commit_objects Module ZODB.DB, line 653, in commit Module ZODB.FileStorage, line 1303, in transactionalUndo Module ZODB.FileStorage, line 1312, in _txn_undo Module ZODB.FileStorage, line 1405, in _txn_undo_write MultipleUndoErrors: Undo error 0000000000000b5c: Undo error 0000000000000b5c: _loadBack() failed Thanks for any help. Chris