Which rooting method did you choose? I usually choose #2 or #4. IIRC, after the NRT puts your N7 into insecure boot, Bootloader should ask you if you really want to unlock the Bootloader. You never mentioned that step, so I'm assuming it stopped without getting that far. You can just repeat the procedure you were trying.
Feel free to call me @707-742-3610 if you want me to walk you through the rooting steps. I know it's a daunting procedure for first-timers. Of course, I'm still not responsible if you brick your N7.