FSX No more engine shutdown sound on the Coolsky DC-9?!?

Hi there

On the Coolsky DC-9 I've suddenly lost the shutdown sound on each engine.
-The sound.cfg hadn't changed, the shutdown chapters are still here, everything seems pretty normal
-The sounds themselves are in the correct sound folder, they play normally from the media player, I hadn't modified them
-The sound device is correctly selected in the FSX sound panel
-All other sounds of the plane are correct

Any idea?
Thanks! I'm lost!!!

(FSX Accel SP2 / W7 64 Ultimate / Nvidia motherboard with realtek audio drivers)
While I do agree that this is not a CoolSky support forum, solving this problem may be of use for later troubleshooting for sound developers. Could it be some kind of memory issue?