I just played a Dungeon Siege game with my sister last night - with
absolutely no problems. Today we tried to play again, but anytime we tried
to host a game, we'd select the game name, click create(/ok/whatever the
button is) and it would think for a little while then jump back to the
multiplayer game type menu (network/internet/gamematch). It's so weird
because we just played last night but when we try a second time it just won't
work.