[Zope] Unable to create an instance of zclass within a zclass.

[chas]

Hi folks,

   This is one problem I've seen in the archives several times but
   with no answer/solution (that I could find, anyway) :

   - Created a new product (MyProduct) using the Control Panel/Products
   - Inside MyProduct : created a new ZClass (ClassA) based on ObjectManager.
   - Inside ClassA : created a new ZClass (ClassB) based on ObjectManager.
   - Added a new instance of ClassA to the Zope root using the 'add button'
   - Within this instance of ClassA, tried to add an instance of ClassB
   - Error "Resource not found"
   - Traceback :
  File D:\Zope\lib\python\ZPublisher\Publish.py, line 214, in publish_module
  File D:\Zope\lib\python\ZPublisher\Publish.py, line 179, in publish
  File D:\Zope\lib\python\Zope\__init__.py, line 201, in
zpublisher_exception_hook
    (Object: RoleManager)
  File D:\Zope\lib\python\ZPublisher\Publish.py, line 151, in publish
  File D:\Zope\lib\python\ZPublisher\BaseRequest.py, line 426, in traverse
  File D:\Zope\lib\python\AccessControl\User.py, line 373, in validate
    (Object: RoleManager)
  File D:\Zope\lib\python\ZPublisher\HTTPResponse.py, line 510, in
notFoundError
  NotFound: (see above)

   In fact, just how are the zope permissions objects used in this context ?

I've looked at KmNews and even tried copying that (adding other objects
to the Subobjects tab) but can't see what the key is, short of offering a 
sacrificial hedgehog to the zope gods.

thanks for any help,

chas