Okay, just on a hunch, I downloaded GWX 2.0 again and installed it to a dummy directory. Then I took the "Terrain" folder out of the "Data" folder and moved it to my real "Data" folder. That fixed the problem. I must have had a corrupt download or install of GWX. That makes me wonder, what else is not right?....
Anyway, thanks for your responses. If not providing the solution, you all at least got my two brain cells thinking in parallel.
