Jon Erickson writes:
...
version: Zope-2.4.3 binary packaged with python 2.1
Use at least Zope 2.4.4 and Python 2.1.3.
You problem report looks like a memory corruption which is a well known
problem for Zope 2.4.x (x <= 3) and Python 2.1.x (x <=2).
Dieter