I just checked out and rebuilt the latest a2dpd. If I run it as root, it works perfectly. If I run as a user, I get these errors:
> a2dpd -o --debug
...
A2DPD[08:30:24.064]: a2dp_make_listen_socket: (errno=13:Permission denied)Cannot bind socket 6 for psm 25
A2DPD[08:30:24.064]: main_loop: *** Cannot get AVDTP socket, incoming AVDTP connections are impossible ***
...
A2DPD[08:30:24.075]: main_loop: Bluetooth Device Settings [44100 hz, 2 channels, 16 bits]
A2DPD[08:30:24.081]: a2dp_make_listen_socket: (errno=13:Permission denied)Cannot bind socket 8 for psm 23
A2DPD[08:30:24.081]: avrcp_new: Listening for AVRCP on socket -1
And then a2dp works, but avrcp does not (I'm using a BlueAnt X5 Stereo headset).