I own the GOG version and it won't launch the game and errors out.
Seems like it's broken there.
Viewing post in Leap of Faith - Complete version comments
Go back to GOG and re-download it. There have been updates to address this issue as many members reported the problem. Also. Check the confirm integrity option during the installation. Any files that are corrupted will be listed and you can use that information to share with GOG so they can review and correct that download file group as needed. My GOG installation for Leap of Faith is running great since last update.