At the moment ist looks like followung:
PenDrive with AUDIY STYLES CAN BE INSTALLED.
PenDrive with additional SD Styles can not be installed (Error 105)
The manual say, that the Styles should be for Sd 9/90/60 …
I just did a quick search on that file extension, and it looks like you are right regarding possible encryption. Well, at this point, I’m out of ideas. No clue if Ketron is open or not due to Covid? The only place I can think of that could help.