Hey, what happened to the Ground Plane? (Forest Winter)

Old product. I purchased it in 2013. I've used it more than once. Most recently, I think, late in 2015. Had no problems, although it's one of those products that send you all around Robin Hood's barn to find various .obj or texture files. 

This time I try to load it, and it demands the texture for the ground plane (no surprises there), and… there isn't one! There is no .jpg for the gound plane. Nothing. The original product of the Forest has one (it's mostly green). The Autumn Forest has one (a browner green). The Forest Superior has something that calls itself Ground-Tree, and seems to be a much darker green, but I don't think that's it. There is none for the Winter Forest. 

I should think that there *was* one, since the ground is not green in winter, but I cannot find it. I re-downloaded one of the versions and there was no ground plane texture in that either. And the program certainly believes that there ought to be one, because it demands it. What happened to it?