Domain and Automatic Updates

I have a Domain ( AD) running on Windows Server 2003 servers with both a
primary and secondary. I also have a File Server as well with Server 2003
Standard Edition.

My problem is with automatic updates. All all pc's added to the domain they
have been set to autoupdate through group policy at 6 p.m. but none do
autoupdate except when manually update is run through the browser.

I have made the changes on the primary domain using group policy editor

If I look at any of the PC's they are set to autoupdate at 6 p.m. BUT not
one will update. However the servers all are set to autoupdate at 6 p.m. and
they do all autoupdate. Any ideas on something I missed?