Honda civic 2.2 CDTI 2006 won't start after battery went flat, local mechanic put diagnostic machine?

Fault on diagnostic machine Immobilizer system is not normal:
SYSTEM CHECK CODE: C-1 IMOES Unit is not registered.

Possible failures:
The MPCS/MICU/IMOES Unit was not registered correctly

Hi so what did he find with a diagnostic tester which is probably nothing like as good as a HONDA one.
this is when it really pays to go to the makers dealer.
as poke and no hope always results in spending more money than was needed.