This particular rss isn't working

I was wondering if anyone can tell me why this rss address does not work on groupsite.

Problem: The module can not be added as "http://www.blogtalkradio.com/zmglobal.rss" as it will continuously give loading icon, then refresh the page with errors and 2nd refresh does not show it at all.

As just "http://www.blogtalkradio.com/zmglobal" it claims it can not find a feed.

Any help would be great :) For the time being we are using a widget, but it's not the ideal look we want.

Thank you!!