I solved my problem with error 52003, so I thought I´d let you all know how I did it.
It turns out Norton Antivirus was the problem.
If you use Nortan AV, open it and go into Options. Under "Internet," click "Program Control," then click "add." Use the Browse box to find Nintendo´s WFC program (usually C:\Program Files\WifiConnector) and choose NIntendoWFCReg.exe. When a popup asks "What do you want to do?" choose "permit," click "OK," and you´re done.
If you don´t use norton, but use a software firewall or another antivirus program, try to make sure NintendoWFCReg.exe has permission to access the internet. Good luck!
Il dit qu´il faut aller dans les options de norton antivirus, aller dans "internet" puis "program control" et cliquer sur "ajouter" utiliser le browser pour ajouter NIntendoWFCReg.exe, quand il demande que voulez vous faire? choisissez "autoriser" et "ok"
Sinon il dit que bien sur si vous utilisez un firewall il faut autoriser NIntendoWFCReg.exe dedans.