Installer error.

Whenever I download the installer and run it, I get this error:

1804097-KXCZVE1.png

I'm running Win 8, with Norton Internet Security. I'm connected to the internet. I've disconnected/reconnected multiple times, downloaded the installer a few times, but I can't seem to figure out what's wrong. What can I do to fix it? Do I need to open ports? How do I do that with NIS?