Cant hear other people's guns in MP

[Randers 10]

Hello,

So here goes.

I cant hear other peoples guns in arma 2 Combined operations when i play multiplayer, but i can hear my own and the ai's guns. this goes for addons weapons and so for normal Arma 2 weapons, i would really happy to hear it cause i would be really sad if i have reinstall the whole thing.

Thanks in Advance.