I agree with Comcast... once you get to your 9th hop, you're out of the Comcast realm.
Since an anonymizer works, I *suspect* that you're probably hitting a firewall or blacklist somewhere out there.
Can you get the IP address for the site? If so, trying accessing it directly (
http://192.168.1.1). That eliminates DNS entirely.
You'll probably need to follow up with the website host to see what's going on.