It sounds to me like a classic USB installation issue. I've seen similar things happen to printers and scanners.
Damn, if only I could remember exactly how.. but anyway, it ususally has something to do with a botched install that never uninstalls because it has more to do with USB than it does the actual device. Try googling some manual uninstall instructions for the adaptor. Sadly, it's so new, there probably isn't much out there.
Mario, I saw this on the Nintendo boards...
"Ok, i found a way!Insert the disk, then go to my computer right click it, and go to explore/ browse. Then go to the Nintendo WFCreg folder, then soft AP, then click on DEVremove, just keep clicking yes, and ok! then retry it! hope that helps! =D"
If you haven't tried it yet, there is a chance that that will uninstall it enough to solve your problems... I kind of doubt it though.