Did some testing last night by killing tasks in the task manager then running MTW/VI on my Windows XP home SP1a machine (rebooting in some cases to provided a clean start list). I recently had upgraded the windows update manager in anticipation of the SP2 release and I noticed that consistantly killing that process in the task manager before launching MTW/VI offered dramatic increases in stability when finishing a year end cycle and going into the menu system to save the game. The process starts with a WU, but I forget the proper name of the exe file.

This isn't exactly production quality troubleshooting and isn't what I like to see in documentation, but hopefully it helps (sure has helped me out).