Actually...I just ran into this issue a couple days ago, and I was thinking about this topic when I did!
The problem? Someone had The Weather Channel installed on their PC, their Internet connection went down, and when The Weather Channel doesn't have an Internet connection, it seems to freak out Microsoft Office for some reason. Makes sense? It didn't to me either, but then again, a lot of those weather programs can be classified as "bloatware" for good reason...