[Zope] Problem migrating a producto to Zope 2.3

[Jorge Ferrer]

Hi all,

I've developed a product for an Intranet using Zope 2.1 and I'm trying to 
migrate to Zope 2.3. Almost everything han gone fine as I haven't used any 
advanced feature, but I have some problems with the ZClasses which inherit 
from OFS:File.

BTW, the product consists on a container ZClass and several other ZClasses 
which represent different types of documents. 

Here is what I've done: I installed Zope 2.3.1 on a new machine and 
installed my product through a distribution file placed on the products 
directory. When I make an instance of the Container ZClass everything goes 
well and I can even make instances of some of the other ZClasses. But 
everytime I try to make an instance of a ZClass which holds a file (by 
inheriting from OFS:File) I get the following error:

===========================
Error Type: TypeError
Error Value: unsliceable object

Traceback (innermost last):
  File /usr/lib/zope/lib/python/ZPublisher/Publish.py, line 223, in 
publish_module
  File /usr/lib/zope/lib/python/ZPublisher/Publish.py, line 187, in publish
  File /usr/lib/zope/lib/python/Zope/__init__.py, line 221, in 
zpublisher_exception_hook
  File /usr/lib/zope/lib/python/ZPublisher/Publish.py, line 171, in publish
  File /usr/lib/zope/lib/python/ZPublisher/mapply.py, line 160, in mapply
    (Object: HtmlDocumentCreationPage)
  File /usr/lib/zope/lib/python/ZPublisher/Publish.py, line 112, in 
call_object
    (Object: HtmlDocumentCreationPage)
  File /usr/lib/zope/lib/python/OFS/DTMLMethod.py, line 189, in __call__
    (Object: HtmlDocumentCreationPage)
  File /usr/lib/zope/lib/python/DocumentTemplate/DT_String.py, line 538, in 
__call__
    (Object: HtmlDocumentCreationPage)
  File /usr/lib/zope/lib/python/DocumentTemplate/DT_With.py, line 133, in 
render
    (Object: HtmlDocument.createInObjectManager(REQUEST['id'], REQUEST))
  File /usr/lib/zope/lib/python/DocumentTemplate/DT_Util.py, line 334, in eval
    (Object: HtmlDocument.createInObjectManager(REQUEST['id'], REQUEST))
    (Info: HtmlDocument)
  File <string>, line 0, in ?
  File /usr/lib/zope/lib/python/ZClasses/ZClass.py, line 543, in 
createInObjectManager
    (Object: HtmlDocument)
  File /usr/lib/zope/lib/python/OFS/ObjectManager.py, line 265, in _getOb
    (Object: CatalogAware)
TypeError: (see above)

===========================

Doew anybody know what it means? How could I solve it?

Any help will be greatly appreciated :-)

Jorge