Vista - Warcraft 3 LAN problems

Hi there, we're trying to play W3 multiplayer via LAN at home,
my two brothers have Windows XP and when turning off Firewall
completely, they can see each other and can join the game.
On the contrary, my third brother did the same with in his notebook,
turning off the Firewall, but he can't even see them. I myself have
Vista Home Premium 32-bit and I can't see them as well.
We downloaded the same version of game, and the same new patch
1.22a. And we really don't know waht to do, have tried changing port
numbers, installing DirX, changing compatibility with the system = none
helped. Please, now it's tome 4 u :-)

Thanks a lot
peter