Group Policy Event Log Error

Hi,
About once a week I get the following error appearing in the event log of my W2k Sp3 server.
Event Type: Error
Event Source: Userenv
Event Category: None
Event ID: 1000
Date: 09/06/2003
Time: 11:53:57
User: NT AUTHORITY\SYSTEM
Computer: SELECTMAIN
Description:
The Group Policy client-side extension Security was passed flags (17) and returned a failure status code of (1208).
I find that if I run the security configuaration and analysis mmc and reconfigure the server this message clears for a while but comes back again after a few days. What can I do to prevent this happening ?
Don…! 😉