[Zope-CMF] portal_calendar is invalid [Zope 2.5.1, CMF13b2, Plone099]

[Juergen R. Plasser / Hexagon]

Hi!

I have installed Zope 2.5.1 and CMF 1.3beta2. I added a CMF site and a 
Plone (Plone 0.99) site, then in the CMF site I added a CMF calendar tool. 
After that I deleted my Plone site (I changed some values/skins and wanted 
to clean up the site to start right from the scratch).

When I now add a Plone Site I get the following error message from Zope (it 
is version 2.5.1 not 2.5.0 as the path may suggest):

Error Type: Bad Request
Error Value: The id "portal_calendar" is invalid--it is already in use.

Traceback (innermost last):
  File /usr/local/zope/2-5-0/lib/python/ZPublisher/Publish.py, line 150, in 
publish_module
  File /usr/local/zope/2-5-0/lib/python/ZPublisher/Publish.py, line 114, in 
publish
  File /usr/local/zope/2-5-0/lib/python/Zope/__init__.py, line 159, in 
zpublisher_exception_hook
  File /usr/local/zope/2-5-0/lib/python/ZPublisher/Publish.py, line 98, in 
publish
  File /usr/local/zope/2-5-0/lib/python/ZPublisher/mapply.py, line 88, in 
mapply
    (Object: manage_addSite)
  File /usr/local/zope/2-5-0/lib/python/ZPublisher/Publish.py, line 39, in 
call_object
    (Object: manage_addSite)
  File /usr/local/zope/2-5-0/lib/python/Products/CMFPlone/PortalFactory.py, 
line 382, in manage_addSite
  File /usr/local/zope/2-5-0/lib/python/Products/CMFPlone/PortalFactory.py, 
line 359, in install
    (Object: plone)
  File 
/usr/local/zope/2-5-0/lib/python/Products/ExternalMethod/ExternalMethod.py, 
line 205, in __call__
    (Object: install_events)
    (Info: ((), {}, None))
  File 
/usr/local/zope/2-5-0/lib/python/Products/CMFCalendar/Extensions/Install.py
, line 108, in install
    (Object: plone)
  File /usr/local/zope/2-5-0/lib/python/Products/CMFCore/utils.py, line 
290, in manage_addTool
  File /usr/local/zope/2-5-0/lib/python/OFS/ObjectManager.py, line 236, in 
_setObject
    (Object: plone)
  File /usr/local/zope/2-5-0/lib/python/Products/CMFCore/Skinnable.py, line 
140, in _checkId
    (Object: plone)
  File /usr/local/zope/2-5-0/lib/python/OFS/ObjectManager.py, line 72, in 
checkValidId
    (Object: plone)
Bad Request: (see above)

How can I fix this?

Regards,
Juergen