Installing RR/RC after 6.1 SS installed extracting SS_RR_RC_part 1 with winrar to this Folder
C:\Program Files (x86)\SEGA\Medieval II Total War have windows 7

! C:\Users\Kung Henrik\Desktop\Downloads\SS_RR_RC_Part1.7z: Cannot open mods\Stainless_Steel_6\Data\sounds\SFX\interface\frontend\back_teutonic.mp3
! C:\Users\Kung Henrik\Desktop\Downloads\SS_RR_RC_Part1.7z: Cannot open mods\Stainless_Steel_6\Data\sounds\SFX\brittania_mission_arrived.mp3
! C:\Users\Kung Henrik\Desktop\Downloads\SS_RR_RC_Part1.7z: Cannot open mods\Stainless_Steel_6\Data\sounds\SFX\interface\frontend\dialog_appear.mp3
! C:\Users\Kung Henrik\Desktop\Downloads\SS_RR_RC_Part1.7z: Cannot open mods\Stainless_Steel_6\Data\sounds\SFX\campaign\end_turn_brittania_01.mp3
! C:\Users\Kung Henrik\Desktop\Downloads\SS_RR_RC_Part1.7z: Cannot open mods\Stainless_Steel_6

to like forever