[ettans]

You can't use format operators in SendClientMessage(ToAll).

Also, I'm assuming by 531 you mean modelid, not vehicleid, so here's the correct solution.

pawn Код:

public OnPlayerEnterVehicle(playerid, vehicleid, ispassenger)
{
  new string[128],
    name[MAX_PLAYER_NAME],
    modelid = GetVehicleModel(vehicleid);

  if(modelid == 531)
  {
    GetPlayerName(playerid,name,sizeof(name));

    format(string,sizeof(string),"%s entered the tractor",name);
    SendClientMessageToAll(COLOR_ENTERVEH,string);
  }
  return 1;
}

public OnPlayerExitVehicle(playerid, vehicleid)
{
  new string[128],
    name[MAX_PLAYER_NAME],
    modelid = GetVehicleModel(vehicleid);

  if(modelid == 531)
  {
    GetPlayerName(playerid,name,sizeof(name));

    format(string,sizeof(string),"%s left the tractor",name);
    SendClientMessageToAll(COLOR_ENTERVEH,string);
  }
  return 1;
}