I haven't used Dirkey, but it looks like a "dialog box extender." Try forum search for previous posts. Alternatives include:
Filebox eXtender http://www.hyperionics.com/
(free and payware)
Listary Pro http://www.listary.com/
(free and payware, but you'd need the payware version)
Of these, Listary Pro is by far the most powerful, and modestly priced for its great power. Filebox eXtender might be closest to what you have now. Both have 64-bit versions: I don't know about DirectFolders.
Apologies for scrappy reply: using a tablet.