PHP Code:
public Action:SoundHook(clients[MAXPLAYERS], &numClients, String:sample[PLATFORM_MAX_PATH], &entity, &channel, &Float:volume, &level, &pitch, &flags)
Should probably be
MAXPLAYERS+1.
And you should change this line:
PHP Code:
if(owner < 1 || owner > MAXPLAYERS)
to
MaxClients to prevent any possible problems.