Everything in the exports folder yes? Not anywhere else, cause if so you'd have to ensure what it is you deleted so it was just the files you added to the game.
The error now is something about it not being able to find a loading screen picture which all games should have, I'm not sure I find any other explanation that you possibly deleted it just now. If other game files would be affected when someone just deletes content that were never in the game in the first place I'd be surprised.
To save yourself the trouble, a consideration about reinstalling FH completely would probably not be so bad.
The file I think you're missing now is
C:\FeralHeart\media\materials\splashscreen.material or possibly .overlay files or pictures in which it uses, noone of them are located in the exports folder though so how this happened I'm not sure.
Checkup if splashscreen.material exists in the given location above, and if it does. I'd reinstall FH if I were you, just making sure you'd make copies of your maps and presets somewhere so you can add it to the new game.
