ok, i see what youre doing.
so you are using fastboot but you dont need a command, as in you download the .tar, then extract until you are in a folder with the jwr66y.zip and bootloader.img and there should be a couple scripts and a flashall.bat
just have your n7 plugged into pc and in fastboot mode
then click the flashall.bat and it will run just fine.
(its been a while since ive flashed a rom.zip to a device, the other command i gave you will work in ruu mode only i believe)
Let me know if this works for you!
All is well, I flashed back to 4.2.2 and can once again do as I please. @demkantor, my thanks!