you have to unzip the package to the Unreal tournament folder, coz the zip file contains already a "system" folder.
look in ur UT\system folder if there is a another "system" folder included.
If that's the case just copy the files into the "real" UT\system folder.
look in ur UT\system folder if there is a another "system" folder included.
If that's the case just copy the files into the "real" UT\system folder.