I faced the same error of "Curl Error (6): Couldn't resolve host name". I tried again and again and every time in the middle of downloading, this error occurred and I had to cancel the setup. I tried firewall deactivation, VPN and other many suggestions on various forums but couldn't resolve the issue. Then I tried again and started the setup. When this error occurred, I simply closed the dialogue box of error. I double clicked on .exe file again, and started the setup without doing anything else. The setup started again from there where it stopped and the whole game downloaded and installation completed without any error occurring again. Now the game is completely installed and I am playing it without any bug or error. I downloaded Flaming Cliff 3 trial version after this and everything is working good and smooth. I recommend to just start the setup again and game download would complete on the same path initially started.