I do not Know whether my explanation are clear or not
It's wasn't.
I Just Know That I have bought a piece of software That is not stable.
You don't. The software is very stable, and of course you can verify it is before purchasing it, because there's a TRIAL.
I have mode all my test With pmdg 777-200. Apparently Gsx Works at some Doors and not at others (could you please confirmer ?).
The PMDG 777 is an internally supported airplane, so it doesn't require any customization on your side, and it works with all doors, and nobody ever reported a problem with it.
Those that had problems in the past, were all caused because they tried to configure it themselves as soon as the airplane came out BEFORE we added support for it, which happened a couple of days after the PMDG 777 was released so, those that had already customized it manually before internal support for it was added, had to remove their customizations.
So, the only possible reason I can think of that GSX works on some doors, but not others, is that you tried to configure it, and made some kind of mistake.
Since there's no need to customize the PMDG 777, you can try to use the "RESET" button on the GSX airplane configuration page, so it will revert to the default configuration that comes with GSX, Undoing any possible changes you made.
If still doesn't work, then clearly specify what do you mean with "Works at some Doors and not at others". What happens when it "doesn't work" ? But report about this only AFTER you RESET the configuration to remove any changes you might have made to it.
Are you sure there is no issues With the French version of FSX
Nobody ever reported them before, and I can't see why there should be any issues with it, we have users with the Japanese version, and they use it just fine.