if you want to use 'Preview' & 'Play' buttons, the files needs to be stored above public_html.
Therefor you should not change the absolute path. The field should be empty.

The jpg und the mp3 file should be stored inside /phocadownload/ and /phocadownloadpap/ folder.
In File Edit view both files should be set like my screenshot #2.
If this all is proper setup there is no reason, why it not work...
So check all settings again..
Kind regards,
Benno