1) Do you have CivIV Complete (or a similar bundle version)? 2) Have you updated your game to the latest patch (3.19)? (Steam does for you automatically, so you might've forgotten this for the disc version... and *don't* trust the in-game updater, it's dodgy.) 3) You should have have it the right folder, the installer takes care of that - but if you want to doublecheck, it needs to be in the mods-folder that also contains the folders "NextWar", "Afterworld" etc., i.e. the other mods that come with BtS. Cheers, LT.