Wait a minute, ... Both you guys are named Henny? I mean,...that's great... and run zope on winMe...
Not to mention that we 're both from the Netherlands, have exactly the same problems. Weird was the first thing that came to my mind ;)
I have tried to use data.fs from my WinMe machine on win2K at work. No luck. The WinMe data.fs comes from a Zope version: Zope 2.2.2 (binary release, python 1.5.2, win32-x86) and the win2k zope is more recent. Zope wouldn't start when I copied it to /var. Shouldn't this work going from 2.2.2 to 2.3 (backward compatability)? Or is the problem the OS: FAT vs NTFS?
I copied data.fs from Win95 to Win98 to WinNt to WinMe without problems (mainly Zope 2.1.6, but the data.fs should be backward compatible). We have also a Win2000 machine running Zope but we never copied a data.fs to that thing. Did Zope start before you copied the data.fs? Have you tried to export and import your sites/folders? Have you tried to copy the whole website directory from one machine to the other? How large is your data.fs? Henny