1. First, stop your Zope instance (otherwise, you will not be able to open the Data.fs as it will be locked).

2. Then go to a command line (Start->Run->cmd in Windows, or a command shell under Linux).

3. Change to your Zope directory (e.g., C:\Program Files\Zope in Windows, or /usr/local/zope under Linux).

4. Make sure that your PYTHONPATH environment variable is set appropriately:

Under Windows:

C:\Program Files\Zope>set PYTHONPATH=C:\Program Files\Zope\lib\python

Under Linux (assuming bash shell):

[user@machine zope]$ PYTHONPATH=/usr/local/zope/lib/python;export PYTHONPATH

5. Run the python interpreter:

Win:
C:\Program Files\Zope>bin\python

Linux:
[user@machine zope]$ bin/python

6. At the Python prompt, you will need to import a few of the relevant modules:

>> from Zope import app
>> from ZODB import POSException # if you're getting a POS Error

# you will also need to import the modules for any objects you need to work with, e.g.,

>> from OFS import DTMLMethod # if it's a DTML Method causing problems
>> from AccessControl import User # if it's a User Folder causing problems

# if you need to find the appropriate module, look for the objecttype.py in the PYTHONPATH you set earlier.

7. You now need to load your root object:

>> root= app() # "root" contains your root object
>> obj= root.unrestrictedTraverse(url_to_obj)

# replace url_to_obj with the relevant path from your Zope root to the folder throwing the POS exception, e.g., ('/somefolder/problemfolder')

8. Assume, "obj" now contains the folder with the dangling reference; we must find the id belonging to the reference:

>> for id,val in obj.objectItems():
...     try: val.getId()
...     except POSKeyError: break

# "id" should now contain the id with the broken object.

9. You can now delete the "bad" object:

>> obj.manage_delObjects(id)
>> get_transaction().commit()

# The second line is necessary to save your change.

10. In my case, I needed to re-create the bad user folder object:

>> obj.manage_addUserFolder('acl_users')
>> get_transaction().commit()

If you needed to re-create a bad DTMLMethod, it would be something like:

>> obj.manage_addDTMLMethod('method_id')
>> get_transaction().commit()

The script is not complete. You must import "POSKeyError" and
"DTMLMethod" and provide "url_to_obj".

11. You can now exit out of the Python command shell (Ctrl-D on Linux, Ctrl-Z then Enter on Windows). Restart your Zope instance, and try accessing the formerly inaccessible object. Hopefully, things will now work for you.