DirectPlay and SB w/ XP

I upgraded to XP this past summer. Not that many issues have occured but one has been plaguing me since the start. When I go to play a MP game, In FS2K2, I start a session and have to enter 127.0.0.1 in the IP address field. Click host and it loads fine. I go to SB and start a session. When it asks me to enter my IP address in the search field I just hit enter. This stalls SB and I eventually have to close SB out and open it again. The only way I can get it to work properly is to go back into FS and under the MP options, copy down the IP address that shows on the host options. Paste that in the SB search field and it works like it should. I have to do the same thing with FSNAV to get an MP session going. I thought it was the Directx version so I upgraded to 9.0b, but it still does it. Must be some setting in XP, but I don't know which. Anyone know of a fix?