Forcing users to log off after inactivity - using winexit

From: bla (bla@bla.com)
Date: 02/05/03 

From: bla <bla@bla.com>
Date: Wed, 5 Feb 2003 16:15:00 -0000

Specifying Winexit as the screen saver for all users via active directory
on a domain controller creates the following error message on the clients
computer.

"Error encountered while creating regestry keys. Make sure you have Set
Value and Create Subkey permissions."

after clicking OK to clear the error Winexit runs as normal prompting the
user that they will be logged off after 30 seconds.

How do we prevent this error from happening so Winexit runs automatically
with no user intevention required?