Thank you Eric and Luis for your help. I figured it out. I always create a Projection folder, Terrain folder, and Plan folder at the start of a project. So far so good, but when I created my terrain I didn’t use the default directory, but sent it into the Terrain folder I created, so the geometry was looking in the wrong location for the terrain and that is why I kept getting that error message. Hopefully this helps anyone else who made this mistake.
Thanks again.