[Zope] Newbie question

I'm passing a record to a python script to alter the variable names in the record (using the :records function). The script works when I insert the record manually, but when I pass it from dtml I get a 'replace' error. I think it's because the record is not a string so it can't be used with the string.replace method. How do I pass the record as a string? This is driving me nuts, I hope someone can help me. Many thanks, Matthew.