[Zope] Duplicate Class IDs

[Ben Ocean]

Hi;
I get this when I restart Zope:

2001-11-13T18:37:56 ERROR(200) Zope Couldn't install EMarket
Traceback (innermost last):
   File 
/apache/ZopeInstallation/Zope_software_home/lib/python/OFS/Application.py, 
line 653, in install_product
     (Object: ApplicationDefaultPermissions)
     (Info: EMarket)
   File 
/apache/ZopeInstallation/Zope_software_home/lib/python/App/Product.py, line 
595, in initializeProduct
     (Object: Products.EMarket)
   File 
/apache/ZopeInstallation/Zope_software_home/lib/python/OFS/ObjectManager.py, 
line 324, in _setObject
     (Object: LockableItem)
   File 
/apache/ZopeInstallation/Zope_software_home/lib/python/OFS/ObjectManager.py, 
line 332, in manage_afterAdd
     (Object: LockableItem)
   File 
/apache/ZopeInstallation/Zope_software_home/lib/python/ZClasses/ZClass.py, 
line 492, in manage_afterAdd
     (Object: LockableItem)
   File 
/apache/ZopeInstallation/Zope_software_home/lib/python/ZClasses/ZClass.py, 
line 446, in _register
     (Object: LockableItem)
Duplicate Class Ids


------
2001-11-13T18:37:57 INFO(0) ZServer HTTP server started at Tue Nov 13 
10:37:57 2001
         Hostname: hermes.thewebsons.com
         Port: 8080
------
2001-11-13T18:37:57 INFO(0) ZServer FTP server started at Tue Nov 13 
10:37:57 2001
         Hostname: hermes.thewebsons.com
         Port: 8021
------
2001-11-13T18:37:57 INFO(0) ZServer PCGI Server started at Tue Nov 13 
10:37:57 2001
         Unix socket: /apache/ZopeInstallation/Zope_software_home/var/pcgi.soc
------
2001-11-13T18:39:13 PROBLEM(100) ZODB Could not import class 'ZMIForm' from 
module 'Products.Formulator.Form'

What is a Duplicate Class Id and how do I fix it?
Also, what about ZODB not being able to import class ZMIForm?
TIA,
BenO