"bad serial number given upon setup"

ok so does this mean that someone stole my key? and if so does it help if I buy a new arma co ?
If someone would answer this it would be awsome!
-thx AksuuZZ

It easy !

1.Run As Admin Steam
2.Right Click on arma 2 oa and you will see properties click on that
3.Go to local files click on verify
4.open arma 2 oa
End Of The Tut

Buy a new key then, add me on skype: DenEkteRobin

2$ each