Error Lotaje

// https://youtu.be/3Y6yApQ1yKU

input double lotaje=0.01;

void OnTick()
  {

  for(int a=0; a<OrdersTotal() ; a++)
     {

     ulong b= OrderGetTicket(a);

       if(_Symbol == OrderGetString(ORDER_SYMBOL)
          && OrderGetDouble(ORDER_VOLUME_INITIAL)>lotaje)
         {

        Alert(_Symbol," ", OrderGetDouble(ORDER_VOLUME_INITIAL));
        ExpertRemove();

         }
    }

   for(int a=0; a<PositionsTotal() ; a++)
     {

        ulong b= PositionGetTicket(a);

       if(_Symbol == PositionGetString(POSITION_SYMBOL)
       && PositionGetDouble(POSITION_VOLUME)>lotaje)
        {

       Alert(_Symbol," ", PositionGetDouble(POSITION_VOLUME));
       ExpertRemove();

         }
      }
}