Ah, I see.
Some more Google searches turned up with this answer:
".QDF are the native quicked files. Quicken never stored it's file as .QIF natively. You have to export the file to .QIF." - Benoit Grégoire
So you'll need to get back to Quicken, load the QDFs, and export to QIF. You can probably use Wine to run Quicken, if you don't have a Windows system anymore.
Last edited by Whyte; 03-04-2009 at 12:37 AM.