[Zope] python.core dump (!) & segmentation fault - Zope v2.5

[chas]

Have just upgraded to Zope 2.5.0 running on Python 2.1.2 and 
am experiencing python.core dumps when I do nothing more than
click on folders (no transactions, no editing). Probably the
best thing about it is that it only takes 8 or 9 clicks 
before it crashes so it's very reproducible. Have run this 
with gdb and got this ~

(gdb) c
Continuing.
Program received signal SIGSEGV, Segmentation fault.
0x8093eaf in PyTuple_New ()

Is this a known bug ? I've imported a few of my previous
packages and that's about it. What should I be looking out
for or is there anything else I can do to debug further ?

Am running on FreeBSD4.4 Release.

Failing my ability to get this running, does anybody 
have a recommendation for a previous, very stable 
version of Zope. I'm still using pre-2.2 at the moment.

TIA.

chas