it happens on diferents maps, im not using mods at this moment, one of those maps i remember it happen its the on that comes whit the game, escape from the island coop for 10 players, and other maps are edited by community

hi mush thanks to response my issue, i try to follow the steps from how to guide, and i put the files on rapid share in this link http://rapidshare.com/files/975852212/arma%203%20alpha%20-%20ID%200002484.rar

and also now i just attached the same file on this

if there something more i can do or if i just miss something please letme know