Don't know really. One day I went to use my Xeditor and the message appeared. The fix was easy enough and I really never thought about it much until I joined this forum and discovered it's a lot more common than I thought.
Microsoft must think it's important...they even have a page on how to fix. Trouble is their solution means dragging out the install disks.
I just chalk it up to another one of those XP features you hear so much about.