Podcasting plugin ‘invalid argument’ error

Hello,

I’m using podcasting plugin to embed mp3 stored elsewhere on my blog.
When any registered user visits the website, everything works fine.
However, if an anonymous user opens any page, it shows an error message at the top:

Warning: Invalid argument supplied for foreach() in /home/…/wp-content/plugins/podcasting/podcasting-feed.php on line 108

Line 108 is
foreach ($pod_formats as $pod_format) {

I’ve never edited anything in this plugin.
I’ve only tried this on my computer.
Sometimes I get an ‘invalid argument’ error on other websites.

Could you please take a look at my website and see if there’s the error message I wrote about?

What could be the problem here?

Thanks in advance!