It probably is permissions on the songs.
Try turning on logging on mt-daapd. Add a log file in your config file. I usually use “/share/hdd/public/mt-daapd.log”, because that sits right in the DISK 1 share, and it’s easy to get to from a client.
Then change /opt/etc/S60mt-daapd and add “-d5”, so it looks like:
/opt/sbin/mt-daapd -d9 -c /opt/etc/mt-daapd/mt-daapd.conf
then run mt-daapd and look at your logfile. It should tell you why it’s not finding anything.