I downloaded the vol.19 skinpacks, but when I then tried to run RoF, I got an error #10027 'Packed data verification' -- it said it couldn't run in mods-off mode. So I then downloaded from the alternate links you gave above (it seems you did manage to add vol.19 links?), in case my original files were corrupted somehow and could be overwritten by clean ones, but still got the same result.
Then I went through all the skins folders, following the readme files for both skinpacks, and deleted every file listed, tried to run the game, still no luck.
I also noticed that there were some stray sub-folders in the Skins folder, apparently mis-named and containing nothing at all ('Brequet 14', 'F2BF2', 'R8', and 'SC'), so I deleted those empty folders, but still got the same error message when trying to run the game.
What can I do now? Do I have to run 'Recovery' from the start menu, which I know will wipe out everything -- all the skins from all the skinpacks, as well as joystick assignments, view settings, preferences, etc.? Or is there some other way to deal with this that's less drastic?