If that service really only works by only providing different DNS servers, then the questions is: does the browser access the webpage by DNS name? Does your siteutil in Onlinevideos do so too? Or are you using the IP directly? If you are also using the DNS name, it would be interesting to know on what IP the DNS resolves in Onlinevideos (you can write a quick logline for it) and to what it resolves from windows command prompt.
offbyone; the browser is not set to use a proxy by itself. The DNS switch has been implemented on my main router. Everything on my network should be using the same DNS servers.
I guess the confusing part is how is it working in my browser?
Only thing I could think of would be IPv6 - if your network your ISP and the site you're accessing supports it, then they go around the DNS resolution from IPv4.