Odd Music on Hold behaviour

I have been setting up and learning about FreePBX for a week or so now in preparation of replacing our aging Asterisk CLI based system (v1.2 i think). I am in the final testing phase and found a rather unusual issue, I have created a new queue and used a test MOH class, if I call the queue internally everything is just fine. However, I tried to ring in over a SIP trunk that I set up for external call testing and the MOH will not play. IN the CLI I get:
[2012-07-12 12:22:26] WARNING[10021]: format_wav.c:146 check_header: Read failed (type)
[2012-07-12 12:22:26] WARNING[10021]: file.c:386 fn_wrapper: Unable to open format wav
[2012-07-12 12:22:26] WARNING[10021]: res_musiconhold.c:329 ast_moh_files_next: Unable to open file ‘/var/lib/asterisk/moh/.nomusic_reserved/silence’: No such file or directory

The intermittent agent announcement still works just no music, all the music has been uploaded via Freepbx Music On hold module and I am on version

From what I can tell this should just work but I am obviously missing something here?

Any ideas?


** EDIT - It appears that you HAVE to set Music on Hold to anything but None in the settings for the inbound route or it will not play any MOH **