I was trying to play Lan with my buddy, we installed PA on his PC and he wasn't signed in, started up a server- but the lobby never loaded; it never let him host. When I tried hosting, it worked, but it didn't show up for him. Anybody know why?
You've probably done this, but check your PA settings and change the (i think its called) local server option from auto to something else and give it a try.
I have found that I have to log in to PA and exit on each computer I want to play. then I log in on the server machine and setup the game. The other computers can just run pa.exe directly. They can set their player name to anything they want as long as they don't include a password. This does appear to have to be repeated after each game or the multiplayer and single player options will not be lit on the home screen.