Error downloading podcast from iPhone

I am having a weird issue.

I produce the following podcast:

http://itunes.apple.com/us/podcast/the-digital-photo-experience/id342516407

When downloading episodes from iTunes on the desktop everything is fine and the episodes download and sync without a problem.

The problem comes in when a user tries to download the episodes from their iPhone directly via the iTunes app. If they try to download the episodes they get a pop-up error message that says "[Episode Name] cannot be played on this iPhone". Replace [Episode Name] with the real episode name.

The episode can be played on the device, since I am able to play it if downloaded from the desktop and then synced.

This was not a problem previous to iOS 4 as far as I know.

Here is my podcast url for iTunes:

feed://feeds.feedburner.com/DPExperienceEnhancedPodcast?format=rss

I am able to download the episodes directly from the iTunes app on an iPad as well so it seems that this problem is related to iOS 4.

ANY help would be GREATLY appreciated.

Thanks,

-J