[Zope] Can't import a ZObjectManager instance in 2.3.3

[Didier Georgieff]

Hello,
I have a simple ZClass derived from ObjectManager (ZObject, 
ZObjectManager).
The ZClass contains 4 other simple ZClass.
I can' t export/import any instance of the container ZClass.
All objects inside the container Zclass can be exported/imported, but even 
an empty instance of my Container ZClass fails.
I'm on 2.3.3 binary win32 but problems are reported with this same ZClass 
on 2.3.3 source on Linux.
Products used are CookieCrumbler, NFGnav,Yihaw, EZportal
Did i missed something on ZClass and Export/Import ??
Traceback is :
The object p1 does not support this operation  

Traceback (innermost last):
  File D:\Zope\Zope233EzPortal\lib\python\ZPublisher\Publish.py, line 223, in publish_module
  File D:\Zope\Zope233EzPortal\lib\python\ZPublisher\Publish.py, line 187, in publish
  File D:\Zope\Zope233EzPortal\lib\python\Zope\__init__.py, line 221, in zpublisher_exception_hook
    (Object: ApplicationDefaultPermissions)
  File D:\Zope\Zope233EzPortal\lib\python\ZPublisher\Publish.py, line 171, in publish
  File D:\Zope\Zope233EzPortal\lib\python\ZPublisher\mapply.py, line 160, in mapply
    (Object: manage_importObject)
  File D:\Zope\Zope233EzPortal\lib\python\ZPublisher\Publish.py, line 112, in call_object
    (Object: manage_importObject)
  File D:\Zope\Zope233EzPortal\lib\python\OFS\ObjectManager.py, line 565, in manage_importObject
    (Object: ApplicationDefaultPermissions)
  File D:\Zope\Zope233EzPortal\lib\python\OFS\CopySupport.py, line 444, in _verifyObjectPaste
    (Object: ApplicationDefaultPermissions)
Copy Error: (see above)

Thanks for any pointer.