If you've waited for a while and/or you receive an error -1101, you may have to follow these steps.
To resolve this issue you must install iTunes 12.0.1. We would suggest that you cleanly remove the current version of iTunes on your PC. You can do this by following these steps.
Reboot, then download and install iTunes 12.0.1 from here.
Once you've installed iTunes 12.0.1 be sure not to update it when prompted, then run TaiG as instructed here.
If you have any questions please ask them in the comments. You may follow iClarified on Twitter, Facebook, Google+, or RSS for further updates.