[Zope-CMF] bizarre Copy Error error

[Rocky Burt]

All,

I've built 3 ZClasses and created content types for each.
  DataLayer (can contain ProjectGroup's)
  ProjectGroup (can contain Project's and ProjectGroup's)
  Project

I create the first DataLayer instance fine
  /myCmfSite/layer1
And I can rename it to whatever I want.

I create the first ProjectGroup fine
  /myCmfSite/layer1/projectGroup1
And I can rename it to whatever I want.

I create the first Project fine
  /myCmfSite/layer1/projectGroup1/project1
But... whenever I try to rename project1 to something else (either by Plone or by the ZMI), I get the following:

  Error Type:
    Copy Error

  Error Message:
    The object project1 does not support this operation.

Am I missing some base classes I was supposed to extend with my ZClasses or something?  I don't get it.

Also, if I create subProjectGroup1 in projectGroup1 I can't rename subProjectGroup1 either, I get the same error (where 'project1' is replaced with 'subProjectGroup1' of course).

Any idea's?

Thanks,
Rocky