Well, it's a recoverable problem. When I open the TE, the entire terrain is colored red, but when I select a texture by checking one of the boxes, the TE corrects to show the correct texture colors. Keeping the TE open, if I open up another terrain, the second terrain is red just like the first was. The same method fixes the second terrain as well. Also, when you Make Map (the clipboard map) the terrain reverts back to all red.