JSI Tip 9493. Windows Server 2003 Service Pack 1 is not available to install from the Microsoft Windows Update Web site?

Microsoft Knowledge Base Article 898767 contains the following summary:

If you try to use the Microsoft Windows Update Web site to update Microsoft Windows Server 2003 to Service Pack 1 (SP1), you could experience problems. These problems can be caused by either a hardware issue or because you are not running Windows Server 2003.