Kill4Free

Hi guys, this is my first post,sorry if i'm wrong in something I just bought Arma 2 CO and installed Arma II first. I played the first mission and it was all normal. Then i decided to install OA too. Here comes the trouble. When i installed OA and played,there was a camera bug. I can move the camera only for looking around,and i can't move it up and down. Also the vehicle's camera is bugged. I'm uploading a video to show you my "situation" Hope you can help me ( hail the dancing banana)

up up:yay: