star wars battlefront II lan problem

whenever i host a game at LAN, my brother cant join. we're both using the same router, and neither of us can see each other's games. whats wrong?

firewall is turned off on both of our computers, and no program is blocking it.

oh yeah, and we can play lan together fine on age of empires 3.

my computer is window vista, and his is xp.

you made sure that the windows firewall is disabled?

you both patched up the game?