If I don't remember it totally wrong, the KN2000 uses 720 DD disks?
Could it be that you now use 1.44HD disks?
Also I seem to remember that if the KN2000 is not updatet, swapped
some "rom chips", it don't read midi format 0 files as direct play.
Description of how to format and save/load is to find at the KN1000
and KN2000 pages at my website.