Vista - Mapping network drives pops up an emtpy Select Certificate box

Hello,
I have 2 business laptops, one has XP, and my new one uses Vista Business. I am able to map a network drive on my XP machine, however when I try to do the same on the Vista laptop, it brings up a box that says "Select Certificate." This box is empty so there is nothing for me to select.

I cannot figure out how mapping drives (to a 2k3 server) would require a certificate on the Vista box. I tried using the straight IP address instead of using the DNS name, but I recieve the same result. I have searched the Web and haven't found any insight on this problem. If anyone has any ideas, that would be very helpful. Thank you!