[Katsunami]

The file system on the Kindle memory got corrupted. It works like a Usb-stick and is treated as such. Next time make a full backup copy of everything on the Kindle memory as insurance against any disasters (if this can still be done), and then let the scan run. It should fix the file system and the problem. A factory reset effectively formats the Kindle's storage, so it creates a new file system, thereby also solving the problem.

This problem is caused when you disconnect the Kindle (or any other storage device) while it's being written to. Make sure you eject (safe remove) it to avoid this problem.