To expand on Matt's suggestions, skip the initial Google account setup, completing the remainder of the initial setup. Then swipe down from the top right side of the screen and tap "Settings" - tap "WiFi" and verify that you are connected to your wifi router. Then tap your "Home" icon (Center bottom of screen) and Chrome and verify that you have internet access. Verify on a PC that you have the correct Gmail address and password. Then on the Nexus 7 go back to "Settings" and tap "Accounts" then tap "Add Account" and select "Google" and enter your full Gmail address and password and it should setup the account without any issues.