Thanks very much for everone's input,
in particular from Bill Norrie! He told me to copy from the SD card to a temp file on my computer, the file marked "private" only. Then transfer this onto an empty SD card which does not need to be formatted, (I formatted mine, FAT only, as Jan suggested).
HEY PRESTO I have ALL my original files reading from the KN7000 SD Card reader!!
So I didn't need to use the Song Manager programme atall!
Anyway thanks again for your help, and I hope all this information might help others too.