I've been trying to fix this problem for a while now; but I just don't understand what the problem is, as I see nothing wrong with the modified spawning.xml: https://pastebin.com/zqa5ynjS
I've also tried verifying game cache, reinstalling the game, and cleaning game data, followed by restarting...
I'm trying to essentially completely change the loot that zombies drop; but despite trying a lot of different things, while playing I'll get this error that says:
EXC ArgumentNullException: Value cannot be null.
Parameter name: Name cannot be null
EXC NullReferenceException: Object reference...