I think this was answered in the discord, but in case you missed it, the script you were looking at was just a different, empty script.
If you click the "Use" button next to the "Cave" hotspot in the Room tab, it'll show the same script from the tutorial.
That error looks like an internal unity thing, you can ignore it. Unity tends to give wierd errors, especially if you're using the latest version, rather than an older, more stable one.