The article you attached above addresses what you should do:
Error 1004, 1013, 1638, 3014, 3194: These errors may be the result of the connection to gs.apple.com being redirected or blocked. Follow these steps to resolve these errors:
- Install the latest version of iTunes.
- Check security software. Ensure that communication to gs.apple.com is allowed. Follow this article for assistance with security software. iTunes for Windows: Troubleshooting security software issues.
- Check the hosts file. The restore will fail if there is an active entry to redirect gs.apple.com. FollowiTunes: Advanced iTunes Store troubleshooting to edit the hosts file or revert to a default hosts file. See section "Blocked by configuration: (Mac OS X/Windows) > Rebuild network information".
- Try to restore from another known-good computer and network.
- If the errors persist on another computer, the device may need service.
Is your iPad hacked or jailbroken? This error can show up in a hacked or jailbroken iPad.