You need to copy contents of ReallyBadAI_Scripts_v5.txt to campaign_script.txt found in british_isles\data\world\maps\campaign\imperial_campaign\. Unless they are already there (they should be at the bottom, look for "Germanicu5" string - if it's found, you don't need to paste anything.).
The setup file may crash, but only if apply\disable operations are performed repeatedly (3 times are usually enough).
Regards