Hmmm, it looks like the program you're using to create the feed (The Podcast RSS Buddy 3.0) is causing a lot of problems. You're feed isn't validating and that's most likely the reason why your podcast artwork isn't showing up.
If you can edit your feed so that it validates, then I'm sure everything will fall into place.
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" podcasts
*Nominated for "Best Video Podcast" in the 2007 People's Choice Podcast Awards
http://www.therestofeverest.com
"Beyond the Movement: The Pilates Podcast"
http://www.thepilatespodcast.com