In fact your iTunes Store page is at https://itunes.apple.com/us/podcast/dj-master-mixs-tunes/id593304839?mt=2
For reference your feed is at http://mastermixpodcast.podomatic.com/rss2.xml
I checked your latest episode. It did play in the Store web page, but it took several minutes before it started. Other episodes I checked started playing an a few seconds.
When subscribing the latest episode downloaded and played OK.
When the episode URL is entered in Safari, the ones I checked downloaded instead of playing in Safari as they should - it's better not to force a download, though since other episodes which played OK are the same it probably isn't the cause of the problem.
I can't see any reason why this particular episode should behave differently from the others. I can only suggest taking it up with the people running your server.