No loot in zombies!

Hi guys. So I'm new to all this and I'm trying to learn how to build a good server form my self and friends just for fun. I've seen many videos on YouTube but for what ever reason non of them is working. I tried to increase loot in zombies. Nothing happened. I've killed like 50 zombies and not a single one of them had a loot. Some goes for animals. Tried to increase animal quantity in map but them as well 0. Not a single animal. Even created more loot but no changes. Any ideas why? And maybe someone has a good tip how to do it properly? Cheers guys. I will appreciate any help as this game starts to piss me off already with no loot in it.

I did exactly as in these videos pal. Does not work. Types.xml has no prob i think. But zombies are completely empty. I'm just thinking. Maybe i should save them files in custom folder? I don't know this is so annoying.

Apparently error has in file cfgrandompresets.xml but there is nothing I can do about it. I tried even the original file of cfgrandompresets.xml and even than it shows error. This is the error error on line 223 at column 8: Double hyphen within comment: <!--

I have no ideas how to fix it.