An error?! that is strange. Stranger that it still works for you with an error. Just for clarity's sake, what exactly works for you now?
Being able to access Netflix from your PC should work by just changing the DNS IPs. The iptables commands are required to make Netflix work on Chromecast. Does it work for you?
Can you paste the error in a reply here so I know what you are talking about?
I'm actually out of the house at moment I will try and paste error when I get back. Before I did what you said I couldn't chromecast Netflix from pc or any devices now I can chromecast from pc, ipad, nexus 7. I'm in Australia so not being in the US was stopping me from using Netflix. I am using Unblock-Us so I changed the DNS settings to theirs