[GEM-dev] gmerlin problem

[Jack]

i'm trying to install libgmerlin-avdec-dev on ubuntu 9.10 but i have a
problem.
This is the first time i try to install it. I would like to use it with
GEM 0.92.3.

Here what i did :
I installed debian-multimedia-keyring (with
debian-multimedia-keyring_2008.10.16_all.deb) then add deb
http://www.debian-multimedia.org stable main (for repository sources).

So i select libgmerlin-avdec-dev and try to install from Synaptic but i
get :
libgmerlin-avdec-dev:
 Dépend : libgmerlin-avdec0 mais ne doit pas être installé

In english :
Depend : libgmerlin-avdec0 but must not be installed

Have you an idea to solve this problem ?
Thx.
++

Jack