Howard, the PC version sounds like a nightmare. We do have the old original version of RockSmith for our Xbox 360, and it's good fun to be honest, not sure it teaches anything though, apart from bad habits. lol..
My boy started off using his Bass through it, then nicked my cheapy strat copy and played it to death. He mastered the game, and was incredibly fast and accurate. But take the game away, he couldn't play a note.
If I remember correctly, the 2014 version is supposed to be a bit better on the teaching side of things, obviously, that's if you can get the bloody thing working, as in your case.
At least you still have the Realtone cable, I plug ours into my laptop, and play my guitar through AmpliTube etc.