This message "memory at address xxxx couldn't be read" occurs on my system when I try to shutdown my printer's desktop interface.
It seems to be related to a task trying to read a part of the memory which is locked by another task. Don't ask me why memory couldn't be read, it's a nonsense.
I searched the web and read a lot of articles, without success. Microsoft doesn't ever mention this message on their web sites.
Unfortunately, I didn't see any solution other than reinstalling XP, and I can't assure you it works as I never tried.