Clean the disc in a disc cleaner, or just clean it very carefully.
Consider turning Wii Connect 24 off, as I've heard some people say that in some Wiis, it overheats dual layered discs.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS







