Had this happen once a while back. Some scenery addon installer was to blame, don't remember which one, but it blanked the title descriptions.
I think the install failed because it tried to install an entry before some scenery layer number and the description wasn't what it expected (maybe ORBYX?).
I looked in the folder where the scenery.cfg resides and found I had some previous backups from more civilized installations.
Was easier to start with that and manually update the titles for the more recent entries.