I recently picked up the Complete version of EU3, and it installed fine. The loader launches fine, and I even get to the menu screen with no problems.
I then went to the tutorial, and tried to run that and it seemingly freezes the game on an "Adapting history..." loading screen. Granted, it could just be an abnormally long load time (I got impatient after about 10 minutes), but it seems like this shouldn't be happening.
Victoria Revolutions (another game by the same company in the same style) runs just fine, so any advice would be helpful.