I just had a problem where i couldn't open Vizio web pages.
Looks like it was a problem with my default ISP DNS server.
I changed my PC to use the Google DNS server, and could open Vizio pages.
Here is a link about using Google DNS servers:
http/code.google.com/speed/public-dns/
I can't tell from your description if this might be the same "DNS" issue, but you may want to try this.