I have a Z SQL Method I'm trying to call with user_id set to the name of whomever had been authenticated via Zope's authentication methods. If I use dtml-let to assign a value to the user_id parameter, I get an error. But if I use REQUEST.set to assign the value, it seems to work fine. I.e., if I try to build the user_id value with this code: <dtml-let user_id="REQUEST.AUTHENTICATED_USER.getUserName()"> I get this error: Error Type: Bad Request Error Value: ['user_id'] However, if I use this code to assign the value to user_id: <dtml-call "REQUEST.set( 'user_id', REQUEST.AUTHENTICATED_USER.getUserName())"> Everything seems to work fine. So, I've got a working version in the latter, but I don't understand why it works and the former doesn't. Can anyone lend any insight? Sean