Game not loading area right

[picaro12 0]

I just recently bought Arma II on steam to play Day z. I installed everything using the 6 updater and I can make it into a game just fine, however, once I get into the game I can only see part of the world while different parts of the screen never render any graphics, remaining white the entire time. The hud system will still display over top of the missing graphics, but nothing else. I can move around and see different enviroments, but it is still impossible to play this way. Does anyone have any idea what this could be and how I can fix it? I need to play this game!