[Zope] Zope will not start after failed 2.8.1 upgrade

[hpinson at indepthl.com]

Upgraded to Zope 2.8.1 on Fedora Core 2, compiled with Python 2.3.5 
(sitting alongside in the paralell to the system python).  Zope 
started, but with errors.  

Reverted back to my former stable Zope 2.7.7 and Python 2.3.3, but 
Zope will not start at all now.

Running the debugger reveals this. Any suggestions as to how to 
recover. I am at a total loss.

export EVENT_LOG_FILE
EVENT_LOG_FILE=
/var/zope-instance/bin/runzope
Traceback (most recent call last):
  File "/var/zope277/lib/python/Zope/Startup/run.py", line 50, in ?
    run()
  File "/var/zope277/lib/python/Zope/Startup/run.py", line 19, in run
    start_zope(opts.configroot)
  File "/var/zope277/lib/python/Zope/Startup/__init__.py", line 52, 
in start_zope
    starter.startZope()
  File "/var/zope277/lib/python/Zope/Startup/__init__.py", line 231, 
in startZope
    Zope.startup()
  File "/var/zope277/lib/python/Zope/__init__.py", line 47, in 
startup
    _startup()
  File "/var/zope277/lib/python/Zope/App/startup.py", line 96, in 
startup
    OFS.Application.initialize(application)
  File "/var/zope277/lib/python/OFS/Application.py", line 278, in 
initialize
    initializer.initialize()
  File "/var/zope277/lib/python/OFS/Application.py", line 303, in 
initialize
    self.install_inituser()
  File "/var/zope277/lib/python/OFS/Application.py", line 484, in 
install_inituser
    app.acl_users._createInitialUser()
  File "/var/zope277/lib/python/AccessControl/User.py", line 1075, in 
_createInitialUser
    if len(self.data) <= 1:
  File "/usr/lib/python2.3/UserDict.py", line 18, in __len__
    def __len__(self): return len(self.data)
  File "/var/zope277/lib/python/ZODB/Connection.py", line 600, in 
setstate
    self._set_ghost_state(obj, p)
  File "/var/zope277/lib/python/ZODB/Connection.py", line 638, in 
_set_ghost_state
    unpickler.load()
ImportError: No module named mapping



-- 
Harlow Pinson
Indepth Learning
Email: hpinson at indepthl.com
Phone: 505 994-2135
Fax: 505 994-3603