[SuperViper]

You should be using foreach and not OnPlayerUpdate.

Include YSI\y_timers and foreach and make a new timer

pawn Код:

Timer:UpdatePlayer[250]() {
    foreach(Player, playerid) {
        if(!IsPlayerNPC(playerid)) {
            foreach(Player, npcid) {
                if(IsPlayerNPC(npcid)) {
                    new Float:rPos[3];
                    GetPlayerPos(npcid, rPos[0], rPos[1], rPos[2]);
                    if(IsPlayerInRangeOfPoint(playerid, 8.0, rPos[0], rPos[1], rPos[2])) {
                        OnPlayerNearNPC(playerid, npcid);
                    }
                }
             }
         }
    }
}

After you do that, create a new function called OnPlayerNearNPC.

pawn Код:

OnPlayerNearNPC(playerid, npcid)
{
    // Code inside here
}

Enjoy. This is faster than the one above me.