Based on the NintendoDS page the Wii page should work about the same. So you can add items to the cart on the nintendoDS page but not the Wii correct?
If this is the case then either the add to cart is not be triggered, or the recordset is not populated with values since these are the two things that make the add to cart work. If you want to get redirected to your cart after you add an item in for testing you can set the value on line 129 like this:
$ATC_RedirectAfter = "";
Just put the full cart page name including the php in the double quotes, it will then take you there after the item has been added to the cart.
As for the comments on the NintendoDS page it looks like it is using the posted value for the comments, the Wii page is not, here is the value you are using on the NintendoDS page: