Input string was not in a correct format.

  private void btnAddPoints_Click(object sender, EventArgs e)
        {
            double dblPointsReturn;
            int DivisionPoints = 10;
            
             
             dblPointsReturn = (int.Parse(lblTotal.Text) / DivisionPoints);

             lblPointsToReturn.Text = (dblPointsReturn).ToString(); 
            
          
            string strConString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=H:\HND Second Year\Prog in .Net\PID2db.mdb";
            OleDbConnection conn = new OleDbConnection(strConString);
            conn.Open();

            string strSQLUpdate = "UPDATE customer SET points ='" + lblPointsToReturn.Text + "' WHERE surname = '" + lblSurnameCustomer.Text + "'";

             OleDbCommand cmd = new OleDbCommand(strSQLUpdate, conn);
             OleDbDataReader reader = cmd.ExecuteReader();


            reader.Close();
            conn.Close();



        }