[Zope] Zope, PIL, and Poll Problem

When attempting to use the poll product the pie chart displays as a broken graphic. The color boxes appear correctly and everything else about the poll seems fine. I have attempted to use this product under both Debian and Windows with exactly the same results. I have followed the published instructions regarding installing PIL under Windows and don't seem to have any errors. The request which returns the broken graphic is http://localhost:8080/Plone/Portal/poll1/question1/drawGraph?size:int=100 Any assistance would be greatly appreciated. TIA, Marc Stein mstein@egrad.com