Hi Joshua,
you should explore index.php from the Network pane as well as the mp3 file to understand the reason why for those errors (broken HTML and empty file?).
I'd suggest to enable the Moodle Debugging at DEVELOPER level and try to follow the SCORM course and explore the PHP error logs to look for any error coming from Moodle: there's no apparently reason in your content for failures in subsequent LMSCommit() calls in the logs since the subsequent failures are due to network issues or broken response from the server; again, you should follow the network calls in the Browser Dev Tools to look for the response body in the SCORM API callback (mod/scorm/datamodel.php) when you'll read LMSCommit("AJAXResult", "").
HTH,
Matteo