.ini file

In my application, there are two report forms. when closing each report form, the report form write the left, top, height, width into .Ini file, so next time the report will show on position as  that on last time.
When I click a button and produce a report A and close it, then click another button to generate another report B, and close it, thare are no problem.
When I produce report A and than report B, then close A( or B), it is still fine, but when I then close B(or A), I got the TExternalException message.
I find when write the form.left into the .ini file, the error message occurs.

The following is the procedure that write the .ini file

procedure WriteIni(formname : TForm);
var status : integer;
    Ininame: string;
begin
  Status := 1;
  if not assigned(SptIni) then
  begin
    Ininame := ExtractFilePath(ParamStr(0)) + 'fSptIni.ini';
    SptIni := TIniFile.Create(Ininame);
  end;

  with SptIni do begin
    case formname.WindowState of
      wsNormal: begin
          WriteInteger('Support', 'Left', formname.Left);
          WriteInteger('Support', 'Top', formname.Top);
          WriteInteger('Support', 'Width', formname.Width);
          WriteInteger('Support', 'Height', formname.Height);
        end;
      wsMiniMized:
          Status := 2;
      wsMaximized:
          Status := 3;
    end;//case
  if not formname.Active then
    Status := 2;
    {write status information}
  SptIni.WriteInteger ('Support', 'Status', Status);
  {destroy the IniFile object}
  SptIni.Destroy;
  end;
end;


Best regards

PeterShaw