ARMA2 & OA's Steam Thread: All Steam Q's/discussions go here [covered by Dwarden]

[ARMA2 & OA's Steam Thread: All Steam Q's/discussions go here [covered by Dwarden]]

I have both ARMA 2 OA and the BAF exp.

When I try to load the game which I downloaded through steam, I get this

ARMA 2 OA

Failed to load the 'd:\program files (x86)\steamapps\common\arma2operationarrowhead\BAF\addond\air_d_baf.pbo' - decryption of headers failed

Then I click ok

Screen goes black

Bohemia splash logo appears then

ARMA2 OA

Bad serial number given in Setup

Any help please

I'm having the exact same problem.