I don't think there's anything wrong with the code as such - I have copied the code and directory hierarchy and on uploading it to my web server both files download ok. (My files are a couple of jpgs renamed to your m4as).
music.php
Check that both music files have uploaded correctly to the same (correct) folder. Maybe your php version/server settings have stricter naming conventions for number of spaces you can have in a filename; try changing the filenames and corresponding code references by replacing the spaces in the filenames with underscores and see if that makes a difference.
Unrelated issue, but on or near line 84 you may want to place the </a> tag before the </p> tag: (1 : sentimental or florid music or art</a></p>)
