[Zope] Namespace ?

Hi people, I am new to zope and am having a few problems in regard to namespaces (I think). I am using code similar to the following but I get, Error Type: KeyError, Error value: unique. I have created a dtml method with the following code... <dtml-let unique="whrandom.random()"> <dtml-in InsertIntoDB> </dtml-in> </dtml-let> I have a mysql database and the insert statement InsertIntoDB as follows, insert into randoms ( <dtml-var unique> ) I have had a look at the howtos but it still makes it as clear as mud.