Just to add my bit to yours, sorry for hijacking. I have the exact same problem, it's been perfect for months on a scheduled scan, all of a sudden 'can't load safe list' and hangs. As soon as I close the message, it will complete the scan, and yep, it is a pain as it's set to scan when the PC is not in use.
I'm also surprised that you posted 10th Jan and have had no answers.

WinXP SP2
Thinner