[mythtv] upnp music again

[John Pilkington]

I'm still having difficulty with MythMusic's classification system, but 
I do now have some indication of what is going wrong with the upnp 
player.  I've gone back to basics, with the SG set to a folder which 
contains a single mp3 file,

/home/john/Musictest/swallows1.mp3

I have scanned for changes.  The frontend will play it, and I see it in 
the upnp menu.

On trying to play it the upnp log shows:

GetFile - Unable to find 
/home/john/Musictest///home/john/Musictest/swallows1.mp3.
HTTPRequest::FormatFileResponse('') - cannot find file
HTTPRequest::SendResponse(xml/html) () :404 Not Found -> 192.168.0.2: 2

So, where should I look for the duplication of the folder name?

TIA,

John