What do I do? Help needed.

I remember I was having this problem a while ago.

Since the Wii is a double-layered disc, it is harder for the Wii to read the disc properly, so trying to clean the lens of the Wii should work. I also know that Nintendo is (or was?) fixing Wiis for free regardless of the guarantee status, precisly because of this.

First off, I would contact Nintendo. The lenses in launch consoles have been having trouble reading the Duel Layer discs, as Sei put it well, so they may offer some kind of replacement or repair deal.

As for cleaning the lens, rumor has it that a regular DVD lens cleaner, that you can buy from basically any store with electronics, can help the problem. Since Wii isn't a true DVD player, the actual cleaning process won't be completed, but it supposedly helps some. I personally have no experience with it, having a console from last March, so try at your own risk.

My problem was far away of the solutions they proposed me, but I guarantee you that you won't have the same problem as me. If you feel you really need to know, feel free to drop me a PM.
I think you can even send it to Nintendo for free. They would only make a general clean up to your Wii, if I am not mistaken.

Whats their email?