Did you unzip it etc? You didn't set your OS to case sensitive or anything? I'll have to talk to the narrat dev sad to say, I've not heard of the engine doing this before...
Try joining the narrat discord, you might be able to get some info there if you ask!!! Unfortunately I'm only a lowly user of the engine, but I and the dev may be able to help you there! https://discord.gg/f9WJwzQa