[Zope] Upgrade woes and product import problems

[Aaron Louie]

I'm trying to upgrade to 2.3.0b1 from 2.2.5b1... I installed the new version
(according to the ZopeInstall HowTo, just to be safe), which started fine. I
then shutdown Zope (2.3.0b1), moved the default var/Data.fs* files to a
backup directory, then copied my old Data.fs* files over. When I tried to
re-start 2.3.0b1, nothing happened. No debug message either. So I put the
default Data.fs* files back in and restarted successfully.

Fine, I thought, the database files aren't all that necessary. All the work
I'd done on the previous version had been exported to a .zexp product export
file, which were all subclassed from your run-of-the-mill ZClasses (image,
file, folder, object manager, ZCatalog aware) and used DTML for all methods.
No PythonMethods, no FSSessions, etc. So I put the .zexp file into the
"import" folder and tried to import the product from within Zope. I got this
error:

Error Type: AttributeError
Error Value: append

Traceback (innermost last):
  File /usr/local/zope/2-3/lib/python/ZPublisher/Publish.py, line 222, in
publish_module
  File /usr/local/zope/2-3/lib/python/ZPublisher/Publish.py, line 187, in
publish
  File /usr/local/zope/2-3/lib/python/Zope/__init__.py, line 221, in
zpublisher_exception_hook
    (Object: Traversable)
  File /usr/local/zope/2-3/lib/python/ZPublisher/Publish.py, line 171, in
publish
  File /usr/local/zope/2-3/lib/python/ZPublisher/mapply.py, line 160, in
mapply
    (Object: manage_importObject)
  File /usr/local/zope/2-3/lib/python/ZPublisher/Publish.py, line 112, in
call_object
    (Object: manage_importObject)
  File /usr/local/zope/2-3/lib/python/OFS/ObjectManager.py, line 542, in
manage_importObject
    (Object: Traversable)
  File /usr/local/zope/2-3/lib/python/ZODB/ExportImport.py, line 208, in
importFile
AttributeError: (see above)

Here's my questions:
1. Why are my old data files screwing up Zope 2.3.0b1?
2. Why can't I import my product?

Note: I also tried this with 2.2.5b1 --> 2.2.5, same errors.

Any insights? Thanks,
ajl