[Zope] Accessing a Subfolder of a Parent Folder

How do I access the subfolder of a parent folder? I am using the following but cannot seem to access the folder object: <dtml-call "REQUEST.set('parentFolder', PARENTS[2].id + 'Test')"> <dtml-call "REQUEST.get('parentFolder').initialize_vars()"> I get the following error: Error Type: AttributeError Error Value: 'str' object has no attribute 'initialize_vars' I understand that a DTML method cannot be called on a string, but how do I obtain the object that represents the subfolder 'Test'? Any help would be appreciated. Thanks. - Asad