Wii Freeze Up

SOURCE: Wifi problems with Wii and Smash Bros. Brawl.

Nintendo didn't anticipate that so many people would want to play SSBB online. The servers are filling too quickly.

If your connection is fine, then the only thing you can do is wait until Nintendo fixes this problem, which will hopefully happen sooner rather than later.

Online matches involving friends (along with their dreaded friend-codes) is supposed to work fine, though.

SOURCE: Wii Freeze Up

Your Wii has probably overheated. Make sure you turn the wii OFF not to standby mode. When you push the power button hold it down until it turns RED not Orange. Once it's RED let it sit for an hour and cool off. Then try and start it up again after the hour has passed. If you don't have any freezing right away like you are now then you know it's a heat problem. Make sure the wii is standing up in the silver base and that it's not closed inside a cabinet or anything. They need air. Don't sit them on the floor/carpet for any reason. Don't have any other electronics around them that give off heat either as it only compounds the heat problems.

SOURCE: my wii plays all games except super smash bros brawl

THAT DISK IT'S NOT DETECTED FROM YOU CONSOLE THAT IS THE PROBLEM - TRY WITH SOME OTHER FRIENDS DISK IN SAME GAME.