Everything is supposed to be there. Both S1 and S2 content are in the S2 file.
Unless your game is outdated, there shouldn't be any problems with compatibility either.
Try to remove the kmod folder from the game and reinstall it, should work. If not, update the game.
Also, i reccomend using WinRar for extracting because 7-zip sometimes corrupts .package files when extracting for whatever reason. I had that problem with Sims 3 and it happens with Sims 4. So, if that doesn't work, try unpacking with WinRar. Maybe it'll solve it.