title: Exception class EConvertError with message ''' is not a valid floating point value'.
body: <p>Hey can anybody help me with this error please, I can't seem to find a solution.
  Any help would be appreciated. 
  I am working with Windows 8 and Delphi RAD Studio 2010.</p>
  
  <p>If there are more errors then what I'm referring to please feel free to comment on them.</p>
  
  <pre><code>procedure TfrmStats.FormShow(Sender:      TObject);
  begin
   // // Code that connects the     TADOConnection to the database
  // //conDatabase.Close;
  // conDatabase.ConnectionString :=        'Provider=Microsoft.Jet.OLEDB.4.0;Data    Source=E:\[Phase    2]\db_DatabaseStock.mdb;Persist Security    Info=False' ;
  // conDatabase.Open;
  
  // Code sets radiobutton.checked and   checkbox.checked to true to avoid errors   and
   // simplify GUI
   rb2D.Checked := True;
   chkShowLegend.Checked := True;
  
   // Code hides ShowGrid checkbox
   chkShowItemGrid.Visible := False;
  
   //Code hides Stringgrid
   SGStats.Visible := False;
  
       DrawPie;
       **end;**  // The breakpoint is here (Where delphi says the error is)
  </code></pre>
  
  <p>I will also show the code for the procedure being called:</p>
  
  <pre><code>procedure TfrmStats.DrawPie;
  var
  sSQL :string;
  iRow, iCol, iA : Integer;
  dblGT, dblLST, dblValue, PiePercentage : Double;
  begin
   // Procedure used to draw the chart of data
   // Here call Subtotal
   SGstats.Cells[0,1] := 'Sub Total';
   SGstats.Cells[1,1] :=    IntToStr(GetSub);
  
   with qryItems do
   begin
   // Select itemname an populate the stringgrid
     SQL.Clear;
     sSQL := 'SELECT DISTINCT ItemName FROM tblItems ORDER BY ItemName';
     SQL.Add(sSQL);
     Open;
     Active := False;
     Active := True;
  
     if (RecordCount &lt;&gt; 0) then
     begin
       SGstats.RowCount := SGstats.RowCount + RecordCount;
       for iRow := 0 to RecordCount -1 do
       begin
         SGstats.Cells[0,iRow+2] :=   FieldByName('ItemName').AsString;
         Next;
       end;
  
     end;
   end;
   qryItems.Close;
  
    with qryItems do
   begin
   // Select itembookquantity and populate the stringgrid
     SQL.Clear;
         sSQL := 'SELECT DISTINCT ItemName, ItemBookQuantity FROM tblItems ORDER BY ItemName';
     SQL.Add(sSQL);
     Open;
     Active := False;
     Active := True;
  
     if (RecordCount &lt;&gt; 0) then
      begin
        SGstats.RowCount := SGstats.RowCount + RecordCount;
        for iRow := 0 to RecordCount -1 do
        begin
         SGstats.Cells[1,iRow+2] := FieldValues['ItemBookQuantity'];
         Next;
        end;
     end;
   end;
  
   // Code that actually draws piechart
   with chtStats do
   begin
     //Clear the charts series
     while (SeriesCount&gt; 0) do
     Series[0].Free;
  
      //Change title
     Title.Text.Clear;
     Title.Text.Add('Items');
  
      // Add series to piechart
     AddSeries(TPieSeries.Create(Self));
     Series[0].Name := 'PieItems';
  
     for iRow := 2 to SGstats.RowCount -2      do
      begin
            PiePercentage :=     (StrToFloat(SGstats.Cells[1,iRow])/StrToFloat(SGstats.Cells[1,1]))*100;
           Series[0].Add(StrToFloat(SGstats.Cells[1,  iRow]), SGStats.Cells[0,iRow] + ', ' + FormatCurr('0.####',PiePercentage) + ' %', clteecolor);
         end;
       end;  
  </code></pre>
  
  <p>The subtotal is supposed to be an integer. I'm also experiencing an 'Authentication Failed' error when running the program, any assistance would be appreciated. I'm still only a beginner so I may overlook small things or make simple mistakes :D</p>
  
  <p>If I need to add more information to help, please let me know! </p>