Installation:
First of all, find the file called INI.big
this could be in c - program files - electronic arts - battle for middlea earth, rise of the witchking
Or in c - documents and settings - *your accountname* - Application data - lord of the rings, rise of the witchking

Folders might be named different... not sure about this all
If you cant find application data: it's a hidden folder so allow those in folder options

Copy that INI.big file somewhere safe
Then replace the one in the BFME ROTWK folder with the one in the zip file. 

Play :p