Hi all.. frist psot.
I also noticed yesterday that my Madcatz 16X GC memory card doesn't work in the Wii. It's either a contact issue, or a hardware (chip) compat issue - or both.
If you insert the card, the Wii doesn't recognise it at all. But, if you lift up on the card a little, then the Wii will see it, as long as you hold it in place. But even when held securely in place, the Wii has problems formatting and reading/writing the card. Oddly, I also have a Madcatz 1X GC card which works fine!
Anyway, I'm going to replace the Madcatz 16X with a genuine Nintendo card, and see what that gets me.