Here is an image that is about 2/3's complete, with the error I am getting.  The error normally occurs at about this same spot, sometimes a little more, sometimes a little less.  The remainder of the image is simply more of the same.  I also provided a top view (see next post) that shows each object in the assembly room.  It really is a very simple scene, 4 fairly simple terrains, 3 distant lights set to about 35 - 40%, and a camera.  The very far terrain is just out of view to the left.

As for the plugins, no.  The shaders are 2 terrain shaders, for the far terrains I have turned the bump way down.  Both use 2 texture maps with a simple noise mixer.  Nothing else.  This is why I am so surprised it not working.