I tried this already. Made no difference.
It seems that you need to download an app from iTunes before updating to 10.6.6 to get rid of the bug/glitch. I even reinstalled osx 10.6 without erasing the disk then downloading an app and then updating, but it did not work.
Whatever is causing it will only get removed if you erase the disk.
I can recall that this advice was given by some iPhone hackers when installing certain jailbreak apps on iPhone and iPad. When I read the solution, it clicked in my head that this could work.
That is some weird bug. Neither my iMac or my MacBook had this problem. :/
Hugh