Wii Kart

We were asked this question:

We registered our friend codes in Kart and we see each other we can even RARELY get into a room at the same time but after we select our toons the kart we want it says “Disconnected from other player”. Anybody else having this? suggestions?

Our best answer is: I put my wii in the DMZ on the router settings and dcs have dropped significantly (unfortunately they still happen occasionally, but i think that is when Nintendo are messing up and all get dc). If anyone else knows a better answer please let us all know!