[Zope] exceptions.AttributeError on container in ''

[AdvertisingDept]

I am using the Formulator product.
  http://www.zope.org/Members/faassen


I unable to cause a TALES expression 
to contact a pyscript located outside
the form's container.


           --main_folder---formObject
project   |
folder----
          |
           --alt_folder---pyScript


I have a List Field whose items I 
would like to populate using a 
TALES expression.  

The TALES expression calls a python 
script that returns a list of 2 item
tuples (as described in the formulator
help)

When I try to use the test tab, the tales
expression fails. I have tried various 
renditions of the container attribute
but always get the error. . .

exceptions.AttributeError on container in ''

           
  container/alt_folder/pyscript
!error!
  python:container.alt_folder.pyscript()
!error!

These types of expressions work from a ZPT 
sitting next to the form in the main_folder. 
So I am obviously confused about the namespace
available from within formulator.


Could someone clue me in to traversing zope namespace
from within the formulator TALES expression?

Many Thanks