Sometime it works great and sometime there's problem to select a file. The K2000 gives a not ready message or it says the disk is not inserted, you have to select the files twice, even sometimes it's not working at all.
This is probably because you change the floppy disk too fastly.
With some devices you need to wait 1/2 seconds to insert a new file image, otherwise the keyboard don't see the new disk...
In this case to change disk you must eject the actual image (middle button), wait 1 or 2 second, and choose the new image (left/right and middle button).
Remember of this : with true floppy disk changing disk take some seconds. So the fast way (directly right/left buttons) to disk change isn't very well supported by some system.
Anyway i will probably add a new parameter to avoid this issue.
Other possible source : a bad floppy cable.