python script msg: Host is down
means that or BT address is incorrect or headphone is off.
Try remove BT headphone device and add it again after you change
/etc/bluetooth/audio.conf and restart bluetooth
You must first of all create a2dp alsa device using python script before you can use it.
PS
You can find more information on
http://wiki.bluez.org/wiki/HOWTO/AudioDevices