Bug when loading scene

Hi,
I downloaded the island demo but at opening the scene I get the messages:

Assets/Editor/UpdateTreeColors.js(13,29): BCE0019: ‘TerrainLightmapper’ is not a member of ‘UnityEditor’

It won’t let me go into game mode because of this and I don’t really know what this means.

Can anyone help me with fixing this?

thank you

just remove the terrain lightmapper and this script