Reach up to the skies or dig deep below, expand your base vertically... If you're into that kind of thing. Original by Simcra, ported to 0.14-0.16 by Erdbeerbaer. Port to 0.17 started by DeltaNedas and continued by Danacus.
Looks like I did break the mod when trying to include support for Alien Biomes. Still a bit surprising it broke. I suppose you're using the latest version I released today. For now you can downgrade to the previous version until I fix it.
I don't really know why you're having this issue. My mod does add a tile named "underground-tile", so I don't see why the game would think it doesn't exist.
Have you tried restarting the game? Does the issue occur with other versions of the mod? Does it happen without Alien Biomes? Have you tried creating a new game?