Currently their RSS Feed (
http://www.keithandthegirl.com/rss/) is being powered by FeedBurner as per Michael in the
Change RSS Thread. Lately Feedburner has been having some funky issues so that could be part of the problem. With that said, whenever I've had issues downloading podcast episodes on iTunes I would unsubscribe and then resubscribe (This shouldn't delete any of the episodes that are already downloaded into your library). If this doesn't work, you could:
A) Copy and paste the RSS Feed into iTunes (On Mac go To Advanced>Subscribe to Podcast...)
B) Use their Full RSS Feed as mentioned in Michael's thread (
http://www.keithandthegirl.com/rss/full/)
C) Wait it out. Feedburner usually sorts itself out in the end. But I do understand the frustration.