How it going with this one? I assume your knowledgeable. If it's still not fixed, Perhaps their is something goofed in the auto update configuration. I stumbled upon this utility, Dial-a-fix when I was looking to help you. Dial-a-fix is a collection of known fixes gleaned from Microsoft Knowledgebase articles, Microsoft MVPs, and other important support forums, that will assist you in repairing problems with your system. Although this tool is ordinarily meant for power users, technicians, and administrators, it is quite safe to use even without technical guidance (although it is recommended). Simply choose the solutions you wish to apply via checkmarks, and click GO. There are other buttons and tools present on the main dialog as well, such as the policy scanner. All tools and checkmarks identify their purpose when you mouse over them. I can't guarentee anything but I would try this for your problem and see if you can get anywhere.
Admin edit: I don't mind the mention of OneCare, however please do not link to affiliate programs.