Sorry cannot help, head over to the Korg Forum where there is a section for each keyboard they make, very knowledgable users there.
Tip
Backup your files to USB and also to a portable USB hard drive or to another USB memory stick.
I have my Korg USB memory stick with folders for each of the files that are on the Bonusware website plus my MIDIs plus my Backups. Then on my very large USB memory stick I have a Korg folder with an exact copy of my Korg USB memory stick.
Than on my portable hard drive I have another Korg folder yep with all the content.
Then there is the PC where it is another Korg folder
OTT or what.
What you could try is download the latest Korg update file, run it on your Pa and then create the Backup file again.