Remember too, thaat as default firefly will run as user: nobody with group: nogroup.
so the db files and the music files have to be accessable by user nobody and group nogroup.
I found it easier to get around this a little by setting up a user mt-daapd and adding it to a music group. And then letting the files be owned by my own user account and with group music.
Easier to manage I found.
Hope that helps and makes sense?
Kelly