I've tried this method and found it to be filled with errors. Now, don't get me wrong... I don't think it's your fault... I think It's mine. But it underscores the point that it's NOT as simple as it appears to someone who FOUND the exploit and wrote up the instructions
Missing steps include... How do I connect phone to PC, exactly? Turn on USB debugging, sure, but what about mounting the SD? Yes? No? Also missing from the walkthroughs are instructions on where to extract the zip to... PC I assume, but that's not working... So I put it on the phone. That didn't work either.
Vertcobra is right... It's easy, but it's not simple.