Weird Glitch?

[InvisFrames]

Ok, so I bought arma 2 OA, I do not own the standalone arma 2. I was getting some odd glitches, I played single player and picked a mission but the mission was a guy who said ''Walk to tree'' So after half an hour of ''walking to tree'' I gave up. What the hell is going on and why is this so funny?

[Lee Hee Hee]

Buy ArmA 2 itself, not having it causes alot of ingame bugs and glitches.