Note, I'm the developer of CastRoller.

I was able to submit that episode by getting the RSS feed from the podcast's main page (http://castroller.com/Podcasts/BigIdeas) and submitting that directly.

I don't know if PodCastle is able to pick up the MP3 on the CastRoller episode page.

The episode is on PodCastle here: http://podcastle.us/e/CMB5V