Something very interesting... I changed the code as you said, and, as I sort of figured, it didn't work (only because I saw that python has no way to convert strings to ints). But in the process I found something else. If you'll note, on my previous message I had the line: <!dtml-call "manage_changeProperty(numtemp = numtemp + 1)"> On the message you sent me, you had: <dtml-call "manage_changeProperty(prop = prop + 1)"> Note the exclamation mark I added. I added it because, without it, Zope can't find manage_changeProperty. For a little while things seemed to be working, except the error I was getting. But then Zope hung indefinitely (over 20 minutes) for loading a page, so we killed the python process. Upon further testing, I discovered that my line would sort of work when viewing index_html once. If I pressed "change" on index_html without changing anything after that first viewing, Zope would once again hang indefinitely (taking up 98% of the CPU while it was at it). Donner