O Método Add da classe Workbooks falhou

procedure TF_Modelo.ExportaDBGrid(ParaExcel: Boolean);
var
  bm : TBookMark;
  col, lin: Integer;
  sLinha: String;
  Memo: TMemo;
  ExcelApp: Variant;
begin
  Screen.Cursor := crHourGlass;
  DBGrid1.DataSource.DataSet.DisableControls;
  bm := DBGrid1.DataSource.DataSet.GetBookmark;
  DBGrid1.DataSource.DataSet.First;

  //Criar o objeto Excel

  if ParaExcel then
  begin
    ExcelApp := CreateOleObject(''Excel.application'');
    ExcelApp.WorkBooks.add(xlWBatWorkSheet);
    ExcelApp.WorkBooks[1].WorkSheet[1].name:= ''Minha Planilha'';
  end;
  //Enviar primeiramente para o memo

  Memo := TMemo.Create(nil);
  memo.Visible:= false;
  memo.Parent := F_Modelo;
  memo.Clear;
  sLinha:= '' '';
  //Pega o nome da Coluna
  for col := 0 to DBGrid1.FieldCount -1 do
    sLinha:= sLinha + DBGrid1.Fields[col].DisplayLabel + #9;

    memo.Lines.Add(sLinha);

  //Pega as Linhas
  for lin := 0 to DBGrid1.DataSource.DataSet.RecordCount -1 do
  begin
    sLinha:= '' '';
    for col := 0 to DBGrid1.FieldCount -1 do
      sLinha:= sLinha + DBGrid1.Fields[col].AsString + #9;
    memo.Lines.Add(sLinha);
    DBGrid1.DataSource.DataSet.Next;

  end;

  //Selecionar o memo e copio para Área de Trababalho
  memo.SelectAll;
  memo.CopyToClipboard;

  if ParaExcel then
  begin
      ExcelApp.WordBooks[1].WorkSheets[''Minha Planilha''].paste;
      ExcelApp.visible:= true;
  end;

  FreeAndNil(memo);

    DBGrid1.DataSource.DataSet.GotoBookmark(bm);
    DBGrid1.DataSource.DataSet.FreeBookmark(bm);
    DBGrid1.DataSource.DataSet.EnableControls;

    Screen.Cursor:= crDefault;
end;