[Zope-CMF] upgrade problem - cannot delete portal_url tool

[chris]

Hello all,

I'm trying to upgrade CMF, and when I try upgrading from CMF 1.2 to 1.3
or later I start getting KeyError: portal_url. From what I gather, the
CMF URL Tool was moved from CMF Default to CMF Core, and I need to
delete the portal_url object and recreate it under the proper tool,
however ZMI will not let me delete it.

Any help would be greatly appreciated,
Chris