[akib]

First of all, close your first bracket,

PHP код:

if (IsACop(playerid)) //<missing this last bracket close
{
return SendClientMessage(playerid, -1, "Ban khong phai la canh sat");
} 


Second, you might not defined IsACop function,
Like this,

PHP код:

IsACop(playerid){
    if(sInfo[playerid][faction]==Police) // sInfo[playerid][faction]==Police is my variable, replace it with yours
    {
        return 1;
    }
    return 0;
}