After tinkering with with the source code, I found that something in Safari changed to no longer play WAV files. I was able to convert the wav files to mp3 files, update the code to point to the new files, and then it loaded and played successfully.
My days of diving into code and debugging it are long behind me – particularly since I'd have to learn Javascript to do it – and Safari reports that the download is not a valid zip file, so on the whole the line of least resistance is to run it with Google Chrome.
