mevans

I recently downloaded ArmA II from steam and when i open both ArmA II and Operation Arrowhead, i says that it cannot find add-on/buildings.pbo and add-on/animals.pbo I cannot find this problem anywhere please help. Is there somewhere i can download the addons without redownloading the game or another way to play, without redownloading? (and if you are wondering why this isn't in troubleshooting forums is because i can't post there for some reason :/ ) your help is appreciated