Flechette Sound/Effects

I made a Content addon for garrysmod10 from my another account (HL2 EP1 / EP2) and the flechette work
(shoot & damage) but they have no sound and no effect, just an invisible explosion without any sounds.
also if i play ep 1 or ep 2 maps the npcs talk without sound.

i checked all files, all is okay but i dunno why gmod dun use ep1 and ep 2 sounds.

need some help x_X