I got the same errors when updating my wii too.
I have a Dlink 614+ and a Dlink 624 router updated with the newest firmware, both gave the same 32002 or 32004 error.
I tried the channel change i disabled all security etc.
What worked for me was to setup up the wifi connection but edit it and enter in manually the DNS of my ISP and the MTU of my router which for me is 1492. after i did this it has been working like a charm!!
Hope that helps you.