feed validation from sermon manager

Greetings, I’m having issues getting iTunes to accept the podcast feed from the sermon manager page
Dear Podcast Owner

An error was encountered while trying to add your feed, [ http://cornerstoneberean.org/feed/?post_type=wpfc_sermon ].

Please correct the error and submit your feed again. For additional information, please consult the podcast FAQ at http://www.apple.com/itunes/podcasts/faq.html and technical specification at http://www.apple.com/itunes/podcasts/techspecs.html.

One gentleman suggested:
The only problem I can see is that in the ‘enclosure’ tags the ‘length’ attribute is set to ‘0″ when it should be the file size in bytes, and the ‘itunes:duration’ is also set to ‘0’. The former shouldn’t cause any problems, the latter causes the Store not to know how long the episode is – I wouldn’t have thought this was a cause for rejection but you should correct them.

I have no idea what has caused the error. I’m asking you to help ID if the duration issue is indeed an issue, or is something misreading.

I am operating the most current release of sermon manager with upto date WP as well.

Thanks,
nebdude

The page I need help with: [log in to see the link]