Had added a new feed and changed the proxy settings  Log said that it had found 1 new episode, but no download started.
 
"Check for New Podcasts", "Catch-up", "Check/Download Selected Feeds" buttons are greyed out on Subscription Tab.  Downloads show no downloads occurring and icon in system tray does not show download.  However when exiting, message  appears "download in progress, really quit?"  Logfile shows no download occurring
 
So I exit and answer YES really quit.  The following appears in the log: 

Grabber for http://a.abcnews.com/podcast/050919ntl.mp3?CMP=OTC-3V9R06864381 unknown; can't stop it.

 and the program doesn't quit.  Try quit again and it ends.  Restart and things are fine, downloads start running