Santa is correct
If they work in the 3000, and not the 2000, then the floppies were made for the 3000.
At one time, You may have somehow loaded the 2000 styles and setups in the 3000, made some changes, and saved in the 3000. Now they won't work in the 2000, because they are not backward compatible.
There is a way to check what you have on the disk via a PC:
The KN-2000 creates five file types during a save when ALL is selected - CMP, LSW, SEQ, SQF and TM.
The KN-3000 has an additional file type, called MSP, and this is the difference. If a MSP file type shows on your computer, than the files are for the 3000 and upward. Disk File Info/Comparison for the KN-2, 3 and 5000
Could this have happened when you were 'between' KN-2000 keyboards?
Larry SynthZone Map
[This message has been edited by lahawk (edited 02-09-2008).]