Give this a try:
1.) Log in to your WordPress site and click the PowerPress link in the lefthand sidebar
2.) Scroll down to the bottom of the page and click the checkbox next to Custom Podcast Channels and click the Save Changes button
3.) Look at the PowerPress menu in the lefthand sidebar and click Podcast Channels
4.) Click the Edit link underneath Podcast on the next page
5.) Copy/paste your desired link in to the Feed Land Page URL field and click the Save Changes button at the bottom of the page