Just to let you know, in this scenario, its the seasons.lua file that automatically handles the switching of the terrain graphic files. The batch file is only being used to switch the unit or cities bmp files and nothing else.My computer is definitely the problem. I think maybe the bat file was not executed correctly.
Anyway, I will try to reinstall your scenario the following weekend. I'm sure, I will fix that 'bug' in one or another way.
In any case, keep me posted to see if you resolved the problem or not.