List your Wi-fi Problems.

Try disconnecting your firewall, if you haven't already.

Much more information here:

http://www.nintendowifi.com/customersupport/troubleshoot.do?error=52003

 (As you can see there's a nintendo official page where you can paste error codes, and it will tell you about them, that's where I got that from)

Well type that error number in the page I told you, and see what they tell you, I'm afraid I can't help :(

http://www.nintendowifi.com/customersupport/SupportHome.jsp

what are you using a router or a usb connector

what are you using a router or a usb connector