Did you sucessfully root before running the backup?
Hemidall is for the galaxy S series of phones (the ace is not one of them)
If you can get to download mode flash a rom via odin and it should bring your phone back to life. Good news is it sounds different from hard bricking (like with rom manager) as you can get to download mode.
Galaxy Note N-7000 & Galaxy Ace
Waiting for official Note Jelly Bean and CM10 for galaxy ACE (Jellaxy)