Thanks Ron – not sure quite what I was doing wrong, as I was copying the .xml file across each time I made a change to the play lists. There may have been an old copy nestling away in a sub directory – hence the duplicate playlist errors, although the behaviour did not appear to be consistent.
I have now cleaned up the network drive, made sure there is only one copy of the .xml file and everything appears to be working fine.
BTW – I have opted to use the “tweakui” powertoy:
and change “My Computer” -> “Special Folders” -> “My Music” to z: (which is mapped to \mediaslugmusic).
This works beautifully. 😛