Neobican bug. Bacio me totalno u rebus

Code:

function SaveAsExcelFile(AGrid: TStringGrid; AFileName: string): Boolean;
const
  {$J+} CXlsBof: array[0..5] of Word = ($809, 8, 00, $10, 0, 0); {$J-}
  CXlsEof: array[0..1] of Word = ($0A, 00);
var
  FStream: TFileStream;
  I, J: Integer;
begin
  Result := False;
  FStream := TFileStream.Create(PChar(AFileName), fmCreate or fmOpenWrite);
  try
    CXlsBof[4] := 0;
    FStream.WriteBuffer(CXlsBof, SizeOf(CXlsBof));
    for i := 0 to AGrid.ColCount - 1 do
      for j := 0 to AGrid.RowCount - 1 do
        XlsWriteCellLabel(FStream, I, J, AGrid.cells[i, j]);
    FStream.WriteBuffer(CXlsEof, SizeOf(CXlsEof));
    Result := True;
  finally
    FStream.Free;
  end;
end;

Code:

procedure TForm4.exportexel1Click(Sender: TObject);
begin
SaveDialog1.Execute;
if SaveDialog1.FileName='' then
else
if SaveAsExcelFile(Grid,SaveDialog1.FileName) then
    begin
    ShowMessage('Dokument je uspesno sacuvan');
    SaveDialog1.FileName :='';
    end;
    end;

Code:

ASSIGNFILE(unosi[br],('data\firm'+pored[i].sifra)); //pored[i].sifra je string
                        {$I-}
                Reset(unosi[br]);
                        {$I+}
                IF IORESULT <> 0 THEN REWRITE(unosi[br]);  //OVDE JAVI GRESKU

Code:
FStream := TFileStream.Create(PChar(AFileName), fmCreate or fmOpenWrite);

Code:
FileMode := fmOpenReadWrite; // ili samo fmOpenRead