This error is caused by an issue with the firewall of your wireless router.


To solve this error :

You may need to manually set the DNS on your Wii console. To view your DNS settings of your network on a PC, click Start > Run > type CMD and press Enter > type IPCONFIG/ALL and press Enter. On Windows Vista, click Start > type CMD in the Start Search box > click on CMD icon > type IPCONFIG/ALL and press Enter.

You may now manually set the DNS for the Wii console after you obtain the DNS information.