It seems my recent upgrade to WordPress 2.5 has completely erased my RSS feed in Feedburner. I am looking into this issue and hope to have it fixed very soon. In the meantime, if you would like to download back episodes of Dave's Lounge, go here.
UPDATE: I think the Feedburner RSS feed is fixed now, and all the missing files should get repopulated in iTunes before the day is over. Hopefully.