Download, extract and install the firmware file manually from the stickied post at the top of the board. It’s the 4th one down in the gray area. You don’t need the Updater.
But having said that, I doubt whether there’s anything in it that is going to magically help your partner download and play audible files from it. Audible files usually require transfer in MTP mode (Settings > System Settings > USB Mode). Maybe that’s his/her problem?