Something is breaking the enclosure tag of your first episode in the feed. The tag looks like this in the source code:
<enclosure url="http://media.blubrry.com/j_peter_white/content.blubrry.com/j_peter_white/double-email-open-rates.mp39706309audio/mpega:1:{s:8:"duration";s:7:"0:10:06";}" length="5242880" type="" />
There appears to be some junk code following the media file URL. Are you manually copying/pasting the URL of the media file into the Media URL field within the Podcast Episode box of your podcast post? If so, ensure there are no empty spaces after .mp3.