Hi all - thanks for the advice Steve.
So I have solved the problem.
I have done 2 things
1) I installed the SLAVE software on a box with a copy of pub jukebox already on the unit - it was de activated but I have now un-installed as well - in case it was causing some kind of confilct.
2) I have gone over my music library and brought a lot of tracks out of extra folders within other folders !
I then rescanned the music library on the master and copied via usb stick again to the slave unit
This has solved my problem I am not sure if it was the first or second thing that cured the fault either way all tracks now select from the master or slave unit and my music library now has a better structure
Thanks all the best for Xmas
J.R.