You should alwys have Python exceptions enabled when you're modding! Nothing is worse than making a mistake and not having an indicator that something went wrong!
Okay, there's an error, seems one of the cities cannot be initialized. There's sadly no mentioning which city it could be.
BUT I've checked the WB file, and I can see something which might cause the problem: You have barbarian cities.
The barbarian player is always the last possible player. So in vanilla civ, you have the players from 0 to 17. And the barbarian is 18.
But here you now have players from 0 to 49. And the barbarian is 50. But in your WB file you still have player #18 (which does not exist).
-> Open the file with a text editor, and replace the 18 in CityOwner=18 and UnitOwner=18 with 50. That should fix the problem.
...or wait, let me do it, so I can also check it works...'kay, it does, fixed version attached

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