For wiimote netplay(that's what you are trying to do, right?), it needs to be set up differently than gamecube controller netplay. Sorry for this, i didn't get this yet, and i'm not sure i can fix that...
Anyways, on wiimote netplay, everybody needs to configure the assigned wiimote instead of the 1st one. And also all players need the same wiimote setup when i comes to enabled wiimotes and extensions. So if player 1 plays without nunchuk and the 2nd play with nunchuk, player 1 needs to configure wiimote 1 without nunchuk, set wiimote 2 to nunchuk and setup his controls on wiimote 1. Player 2 also needs to configure wiimote 1 without nunchuk, set wiimote 2 to nunchuk, but setup his controls on wiimote 2.
Anyways, on wiimote netplay, everybody needs to configure the assigned wiimote instead of the 1st one. And also all players need the same wiimote setup when i comes to enabled wiimotes and extensions. So if player 1 plays without nunchuk and the 2nd play with nunchuk, player 1 needs to configure wiimote 1 without nunchuk, set wiimote 2 to nunchuk and setup his controls on wiimote 1. Player 2 also needs to configure wiimote 1 without nunchuk, set wiimote 2 to nunchuk, but setup his controls on wiimote 2.