Okay, this is starting to make more sense now. It seems to me that somehow when uninstalling IE 7 MSN is either looking for IE7 still or used a file that was removed when IE7 was uninstalled. I'm not sure if uninstalling MSN and then reinstalling it would work but that is definitely the problem.
I've yet to come up with this exact problem anywhere but the last post in this thread looks like it may have an answer
http://powwow.omgili.com/viewtopic.php?p=610