I’m having the same problem. Not sure if its is because of being on WP 3.8.1 or with the latest plugin, but everything defaults to my theme’s archive.php for rendering all SermonManager content.
What he means (I believe), is that when you browse to <yoursite.com>/sermons … it is the archive.php file that is rendering the view (rather than the SermonManager plugin php files).
The question is, how to fix?