Thanks a lot Alimonster, the domo was very helpful. I get one error with your demo on my system, maybe it's because i'm using Delphi 5?
[pascal]
procedure TfrmPackerMain.btnAddClick(Sender: TObject);
begin
if dlgOpen.Execute then
lstFiles.Items.Assign(dlgOpen.Files);

btnSave.Enabled:= (lstFiles.Count > 0);// i get undeclared identifier: 'Count'
end;
[/pascal]
This isn't realy a problem, i just wanted to let you know.