It's looking for that weapon file and you don't have it in your mods folder.

the weapon file knuckle crack is on my _zombiemode_perks.gsc and idk why its said unknown item: zombie_knuckle_crack u know when u pack ur weapon it crack his
fingers but when i remove the file weapon  and pack my weapon cannot take it or anything

Is this a custom map? I think it's best to use Gympie6's Script Placer to avoid any trouble.
This is the best way to start a custom map.
 

 
However, if you already have a map, follow these steps:
 
Step 1: Generate a map using Gympie6's Script Placer.
Step 2 Choose your preferred options for the map source.
Step 3: Select your preferred features options.
Step 4: Replace the generated .map file in the map_source folder with your existing map.
Step 5: Set up the perk prefabs using Gympie and remove the old ones you currently have.
Step 6: For finalization, review Gympie's instructions.

oh thanks a lot its working perfectly appreciate it bro