Here is what I got from nintendowifi.com :

http://www.nintendowifi.com/customersupport/troubleshoot.do?error=51029&x=4&y=3

If you wouldn't mind, I would suggest turning off Norton while going wifi. I also have Norton, and all I did was add the WFCRegsiter.exe program to my allowed list of programs. To do that, you need to:

1. Open up Norton

2. See if you can find "Option" and click on it.

3. Go to the list that says something in the sense of "Allowed Program". It's probably under Personal Firewall Configuration.

4. Add the WFCRegister and make it so that it's allowed.

Good Luck!