"Please apply a C# Sun Shaft Script to your camera GameObject" -- I have TWO
I already had a first-person "player" in my game, and so I manually added the scripts I saw under the C# pre-fab's Camera to my existing camera. This means that my Camera has two instances of the C# "Sun Shafts" script on it, with the UniStorm Sun_Moon and MoonLight dragged in to each as the "shafts caster".
I also told UniStormWeatherSystem_C my Camera's GameObject by dragging it into the slot.
However, the error message appears indicating that the UniStorm script doesn't see this component.