If there are no files in the "masks" folder, that could be causing your problem. In the link that Lucius linked above, check for the "textures" sub-folder download at the bottom; within that, you will find all of the files that should be in the "mask" folder. You don't have to install them directly into the game yet. You can download that "textures" folder and put it anywhere outside the FeralHeart folder (such as your desktop). I would recommend when downloading to Save and Open, instead of just opening, as you may have installed it but the download closes before you can actually access the files. At this point in the installation, you don't have to download directly into the "masks" folder.
Once it's installed, simply open the file and view the folders. In the "masks" folder, highlight everything and copy them, then go into your actual Feral Heart folder >> media >> textures >> masks, and paste. Close out of the FH application if you have it running and then open it up again. You can try this with other folders on that link, as well-- the "markings" folder, the whole "textures" folder, if you'd like.
If all else fails, you can always go for a complete re-install of the game. If you do so, be sure to save any files you want to keep (screenshots, presets, maps, etc.) in a separate folder located outside of the FeralHeart folder so you can add them back in after the reinstall.
