Hi Heather,
Have you tried opening the xml document of RSS feed you've created in a text editor? Notepad on Windows works and so does Text Edit on a Mac.
Look through it and you'll see where the url of your episode is located. Verify that it's the correct address.
That's the first place I'd start.
Jon
TreeLine Productions
Fort Collins, CO USA
Currently producing these popular podcasts:
"The Rest of Everest" Video Podcast *Voted as one of iTunes' "Best of 2006" & "Best of 2007 Classics" podcasts
*Nominated for "Best Video Podcast" in the 2007 People's Choice Podcast Awards
www.therestofeverest.com
"Beyond the Movement: The Pilates Podcast"
www.thepilatespodcast.com