cowtag - the same thing happens to me a lot as I frequently log in from different computers on different servers and isp addresses. I am not sure how it does it but I guess the software reads the new machine or information and it gives you the message every time it is a new machine. It will happen on my home PC periodically too, and I think that is because our AT&T switches back and forth to a variety of different servers for our network periodically.
Kind of annoying but if you delete the old messages then it will only appear when there truly are new messages.
UTROY
Proverbs 21:19 (why I hunt!)