"FATAL ERROR" when trying to launch MY custom story

[Your Computer]

Every time the game finds a folder in the custom_stories folder, it checks for custom_story_settings.cfg in that folder. If you look at the paths for those folders, you'll see a lot of them are simply directories to store random content in, and so, by purpose, will never have a custom_story_settings.cfg and therefore the error messages can be ignored for those folders.