If the error persists after deleting all mod files and verifying the game, do a clean reinstall of Black Ops 2.
The error related to Buddha.dll in Call of Duty: Black Ops 2 is almost always caused by (especially the popular "Buddha" mod menu for zombies mode), not by a missing Windows system file. If the game fails to load this DLL, it’s because the mod menu installation is incomplete, blocked, or incompatible. How To Fix Buddha.dll In Black Ops 2