If you're doing anything with LUA, such as custom perk icons or a custom HUD, you NEED L3akMod.
Download L3eakMod HERE.
You will also need BOTH VS 2015 and 2013 runtimes (x64 editions): 2015 2013
After downloading L3akMod, navigate to your "root/bin" folder and drag the files in the download into this folder. OVERWRITE everything.