Hmm,
you must be pointing to the wrong directory, probably the base install dir, and not the native dir with the so files...
I haven't tried it on the linux box, but sending the display over network for playing games usually works very badly.
Under project properties go to Run and set VM Options to:
-Djava.library.path=/home/louis/CoursENS/PPOOGL/jpct/ib/lwjgl-0.99/native/
I'm pretty sure that's the problem...
So add native to the end of that path...