Try moving your router closer to your wii. If that doesn't work try all the things in the following guide.
my internet connection is not working, i do the test everytime and it said error code 51330. I have tried everything...please help
also check for basic interference. a 2.4ghz cordless phone can do this (same frequency as a router) so can microwaves and fans. Try to get your router or wii away from these items. hope this helps!