w00t! I fixed the problem by hacking at the PHP. I've attached the fixed version.
The encoding of the URL wasn't the problem. (It's being done with rawurlencode(). Though it was only necessary to encode the ampersands in the url, not the whole URL. The XML is malformed with raw ampersands, but it handles the other characters fine.)
It was the missing Itemid. It looks like the Itemid is related to the Menu item through which you're viewing the study. If the Itemid is missing, it breaks the AVReloaded plugin. So in my copy of the bsms_podcastpublish.php, I added "&Itemid=58" onto the end of the URL. That cleared up the problem.
But I doubt you can just add that for general release. Wouldn't the Itemid be different for everyone? You would have to link the podcast to a particular menu item. That seems fairly difficult. (Or could you add a Menu Item parameter, "Use this menu item for viewing podcasts"? Then it could write its Itemid to the podcast database.)
But this might be useful, if you're going to include the Study URL in the podcast. It will let people control how it displays. And if you don't figure out a way to include the Itemid, there's not much point in including the URL at all!
P.S. I also added this line:
$title = str_replace(' - 0',"",$title);
Because I didn't like the " - 0" that showed up in the title when a Study had no scripture reference listed.
Is this a change you'd like to include for general release?
Attachment bsms_podcast-8b75392abc2c2b54a02856a2c5fd0b17.txt not found