Next time, please post this in the Miscellaneous section of the forum so I can find it. I was linked to this by a friend, hence the late reply.
To make Shiny2 work, you need to set your Primary DNS IP to the IP of your computer. Let's say, your router is 192.128.1.254; it'll assign your PC an IP address of like...192.168.1.64, for example. You set the DNS IP in Shiny2 to that IP address, and then you set your Primary DNS Address in your 3ds to the same IP address as your PC. I cannot stress that enough.
Once done, make sure no firewalls are blocking the ports, and no programs (like Skype) are running that take up Port 80, and then you can use Shiny2!