how to fix a fatal erreur fro broken package

HI,
I often meet the problem for broken package, need a more detail on apt-get and dpkg tools

Here is the last pb,
My laptop stopped suddenly, (forgot to plug power!!! ), while I was installing gdm package,

I got after that the problem, in libdmx1, I have tryed several option to remove it, reinstall it
I tryed dpkg --force-all -r libdmx1,   I tryed to force install, force remove,

I always got the error:

Package is in very bad inconsistent state-- you should try reinstalling it
before attempting   a removal

Reading database .... 30%dpkg;   unreocverable fatal error , aborting
files   list file for package 'libdmx1' is missing final newline.

I tryed dpkg --reconfigure -a
and   again       apt-get install libdmx1         same error

Thanks for help
best regards
bela