GPO option gone AWOL

I've got a strange problem with Server 2k3. Over a year I set this option in GPO to "Go directly to home page".

Computer Config -> Admin Templates -> Win Components -> Internet Explorer -> Prevent performance of First Run Customize settings

In this setting you explicitly set the home page, which overrides the setting in User Config -> Internet Explorer Maintenance -> URLs -> Important URLs.

I want to change the home page that is used throughout the school, however, I've gone in to Group Policy Management and the setting has completely disappeared, so I cannot change it!?

Has anybody encountered this before or suggest a way of getting the setting back to change it.

Thanks in advance