Auto Update through group policy not working

Hi,

I have a 2003 SBS server, with all XP clients. I created a test OU,
under the default users OU, and put 1 laptop in it. I then created a
group policy object linked to that test OU, and in that GPO, I
configured the following policies:
computer config->administrative templates->windows components->windows
updates:
Configure Automatic Updates: Enabled
Configure automatic updating: 4 - Auto download and schedule the
install
The following settings are only required
and applicable if 4 is selected.
Scheduled install day: 0 - Every day
Scheduled install time: 03:00

Delay Restart for scheduled installations: Enabled
Wait the following period before
proceeding with a scheduled
restart (minutes): 15

I have left the laptop on, logged on with a non-admin account, and
locked, for like 3 days now, and it has not updated or rebooted. It
looks like the policy has applied correctly: I have looked in the auto
update settings, and it is grayed out, with the selection I specified
in the policy. also, I did a gpupdate, and a gpresult, and the result
showed the policy i created in effect...yet, still no updating.

Any ideas? Any help would be greatly appreciated!

Thanks in advance.