[Zope] Upgraded to 2.5.1/2.1.3, now I don't get a 'session_data' in 'temp_folder' on startup..

Hows *that* for a descriptive subject line! :) But seriously folks... I've upgraded an installation to Zope 2.5.1/Python 2.1.3 and I get the weirdest error. The 'session_data' object in the top level folder 'temp_folder' does not get created - but only on *one* of my 2.5.1/2.1.3 sites. As this is the most important of our sites, and we use session machinery quite a bit, I tend to notice this rather quickly. Can anyone think of where I might start to look for a solution to this problem? Ta Tone. -- Dr Tony McDonald, Assistant Director, FMCC, http://www.fmcc.org.uk/ The Medical School, Newcastle University Tel: +44 191 243 6140 A Zope list for UK HE/FE http://www.fmcc.org.uk/mailman/listinfo/zope