Call of Duty Black Ops II problems

[Cheezter]

Hi.
I wondered if anyone could help me out with a major problem.
I have just been on vacation in Cambodia. I found CoD BO2 for 7.5$ and bought it.
Now I have come home and installed it, but i cannot connect it to Steam. Multiplayer doesn't work. And when i tried to launch it an error popped up saying that buddha.dll was missing on my computer and i should reinstall the game (which i did multiple times) to fix the problem. Didn't work.