Have an error 4051 in my code and can't find where is coming from

Here's the code for it

//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
//---

//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
void OnTick()
  {
//---
// Checks the time for trading;-------------------------------------------------------------------------------
   if(Hour()> 1 &&  Hour() < 22)   //time condition less than 12am and greater than 2am
     {
      //---------------------------------------------------------------------------------------------------------------------------
      if(AccountNumber() ==  52946085) //check the trading id of the account
        {

         double sum = 0;
         for(int a=0; a <= OrdersHistoryTotal(); a++)
           {
            if(OrderSelect(a,SELECT_BY_POS,MODE_HISTORY))
              {
               sum = sum + OrderProfit();
               if(sum < 49)
                 {
                  double lot = 0.1;
                  double fastma = iMA("",5,3,0,MODE_EMA,PRICE_CLOSE,0);
                  double slowma = iMA("",5,15,0,MODE_EMA,PRICE_CLOSE,0);
                  double checkma = iMA("",5,3,1,MODE_EMA,PRICE_CLOSE,0);
                  double checkma2 = iMA("",5,15,1,MODE_EMA,PRICE_CLOSE,0);

                  // ------------------------------------------------------------------------------------------------------------------
                  //Opening Signal for bullish
                  if(fastma > slowma + 1 * Point && checkma < checkma2)
                    {

                     double openlong = OrderSend("EURUSD",OP_BUY,lot,Ask,3,0,Ask+40*Point,"SXG",7899);
                     SendNotification("OPENED EURUSD");
                     Alert(" OPENED EURUSD");

                     Sleep(300000);//wait for 15minutes
                    }

                  //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                  //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                 }
              }

           }
         //-----------------------------------------------------------------------------------------------------------------------------
         //closing bracket for time check and account check
        }
      else
        {
         //SendNotification(
         SendNotification("Account didnt connect because of: wrong account number");

        }
     }

   Print(GetLastError());
  }