First off, I have some questions:
1. Are you unlocked?
2. Are you root? (Doesnt really matter)
3. Android 4.0 or 4.1?
4. At which point is that error showing up?
5. What about the stock beta ROMs?
6. Did you rename the ROM to update.zip and to what place did you copy it ?
Somebody had the same problem. Im not sure about the solution though.
You can boot into a different recovery (since the message youre gettin' is from the stock recovery).
Search the forum for cwm. Then use fastboot boot recovery-nameoffile.img
It requires an unlocked bootloader.
1: You can, if you are able to boot into Android. If you can't, adb will not work.
To push a file to your tablet, use the following commands:
adb push update.zip /sdcard
Update.zip being the stock ROM, obviously.
2: Yes. That could work. Try to install CWM and you should be able to flash a stock ROM from this thread:
However, you should be able to flash that ROM already. Remember you have to unlock your device. You can, however lock it again by installing a stock ROM; but I heard it will unlock itself after an OTA or flashing another stock ROM or something like that.