[Zope] Probably a simple name space question

Hi all, I'm struggling with a problem in DTML for a day now and I'm ready to beg for someone to enlighten me. Problem: I want to call a Z SQL Method (say InsertFoo) from a DTML Method (say CallingInsertFoo) and it just won't work. The Z SQL Method takes three arguments, let's call them a_id, b_id and c_id. All three arguments are available to me in the calling DTML Method. I can print them in HTML. But when I call the query with <dtml-var InsertFoo> I get the following error: "Error Type: Bad Request Error Value: ['a_id', 'b_id', 'c_id']" I tried all sorts of things but I'm thinking I am missing something obvious. What am I doing wrong??? Greetings, BertJan Bakker