Ok...I think I have it figured out...not sure. BUT this might help you since you said you were using a WOO Theme.
I use a Pro Photo theme and forgot that they offer settings in the customization area that have to do with the feed. There was an option to enter your feedburner in there. So this wasn't a plugin, but part of the customized Wordpress theme I had purchased and was using. I suspect Woo themes has the same. So dig inside there and if you have the feedburner feed in there somewhere, once you delete it your "podcast fee" in Powerpress will go where it should.
I think my feed became too large for itunes because it was being redirected to the feed burner feed, and therefore my latest episode wasn't showing up because it was taking itunes too long to read the page. But with the powerpress feed now working as it should for podcasts, I am hoping that I am back in business. Only time will tell, but my fingers are crossed that was the issue!!
I think it didn't effect things for the first 4 podcasts because of the feed burner feed size, but then as a it grew, it was taking too long to be read by itunes.