I have been using this add-in for several years, and it has been great. I just noticed yesterday (not sure how long it's been happening) none of the players are working on my site any more. They all return "File not found." My files are still in the same folder, and the folder checker says the folder location is just fine.
I did recently change my WordPress Permalink settings to "Post name", but I don't know how that would affect Audio Player. That's the only big change I've made recently.
My site: mandevillechurch.org