[Zope] Zope does not find import

[Steve Hunter]

PersistentExtra.py can't find Persistence, I don't see a file or directory
named
Persistence ? Using Zope-1.11.0pr1-win32-x86.exe

>>> import Project
Traceback (innermost last):
  File "<stdin>", line 1, in ?
  File "Project.py", line 2, in ?
    from Globals import HTMLFile, MessageDialog, Persistent
  File "C:\ZOPE\lib\python\Globals.py", line 90, in ?
    import Acquisition, ComputedAttribute, App.PersistentExtra, os
  File "C:\ZOPE\lib\python\App\PersistentExtra.py", line 87, in ?
    from Persistence import Persistent
ImportError: cannot import name Persistent