Which one? Minidlna from firmware or from Entware\Optware?
Please note that /jffs/script/services-start will be started after last USB-partition is mounted, it ignores SD Card partitions. If you want to delay minidlna start till SD Card will be mounted, you may add:
# Wait up to 15 seconds to make sure SDCARD partition is mounted
while [ $i -le 15 ]
if [ -d /tmp/mnt/SDCARD/SomeFolder ]
i=`expr $i + 1`
to /jffs/script/services-start script.