You have two controllers enabled on the "Gamecube" tab but have only one player in the NetPlay session.
That's right. Though, I tried with only one gamecube controller in the Gamecube tab, and only me as a player in NetPlay, and the behavior is the same (grey window).
Here are the screenshots.
Then I push "Start" and it goes fullscreen grey.
bump

try the same settings on a Windows System.
if still grey screen something is wrong
if it works... HAHA
@dannzen: I don't have a copy of Windows infortunately. Are you saying that the issue only affects the mac version?
little bump

oh look, OSX.
get a real pc.
Now that's constructive.
Let's move on to more interesting replies
