[Zope] zsql question (cannot render query template)

Hi, I have a simple SQL method which just does a select on all rows, ie. "select * from users", which works. for security reasons I want to embed the sql statement in another dtml if- clause, like that: <dtml-if checkperm> select * from users </dtml-if> (checkperm is a DTML method which returns either 0 or 1) when I try to test the SQL method I get the following error: Error, exceptions.NameError: REQUEST SQL used: Could not render the query template! what am I doing wrong? thanks -Oliver