By the way, just about everyone posting here is a voluntary poster. Sandisk employees typically don’t post here very much, and when they do you will see Admin or MOD next to their username. They mostly post here just to announce new firmware or new products, and usually don’t answer questions people have.
The frequent posters here try to be helpful, however I don’t know of anyone who posts frequently here who has experience using protected files. You could try doing several google searches for information about protected files, and try contacting the place you got the protected audiobooks from for advice.
Now that my Sandisk players are Rockboxed, I might not even be able to use any protected files on them(even if I boot the player in the original firmware). Rockbox is an alternative operating system(dual boot, it works alongside the original firmware, so one has the choice to boot to either one) for the player. Putting Rockbox on a player though might make it permanently unable to use protected files. Rockbox for an mp3 player is like Linux for a pc. It provides many more features and settings than the original firmware, but doesn’t support any protected files.
