[ZODB-Dev] cPickleCache: "Cache values may only be in one cache" error

[Andreas Jung]

I am currently working on a Plone 2 application where I get the error 
frequently.
The application is based on Archetypes 1.3. It seems that is has something 
to do
with the so-called ImageField that stores an image and scaled versions of 
the image
as attributes of a persistent object (attributes are OFS.Image instances).
The error occurs when I render all scaled version of the images within 
transaction
in a HTML page.Any ideas what causes this error?

-aj