Environment texture files

I am installing a new route and have received the following error message from Route Riter:
Environment texture file hitw-gray.ace is missing from your route
I have found the file elsewhere and copied it both to the Texture folder for the route and the Global Texture folder, but they are obviously not the right place for the file.
Any suggestions where it should go?
Jonathan

Hi Jonathan
Try placing it in the Textures folder inside the Envfiles folder

Garry

Thanks. That has solved it.
The first time in years I have come across files missing in that folder.
Jonathan