Well I know this Thread might not be frequented much, but im having the exact same issues as Rory.
I install everything for TE 5.1 then unzip SP to my Steam/steamapps/common/rometotalwargold, and when i click on TESP_instalprep.bat it brings up the cmd window for a second then closes.
I have steam so i dont know if that causes problems because when I try to make a shortcut using the .ico it says connot find steam and opens steam on a webpage. I can get TE 5.1 with the Ferres Roman unit skins mod to play, but I feel like im missing out with some of the BI features not included.
If anyone could help me figure this out id be in debt forever. I really like TE but this mod looks like it could possibly make it better.
Thanks in advance!!