Arma won't start, pops up message.

[Ligr 10]

Hey people, I've got this game as a gift, and after installing it today,I'm running into a problem.

I start the game, it shows a box with checkmarks, attempts o enter full-screen mode and then crashes, a message pops up that says: failed to read shader cache file. Missing or broken shdc file?

My computer specs:

Intel dual core Q6600 (I can OC it to 2.9, but I don't think this is the problem)

2GB DDR2 RAM G-Skill

Windows XP SP3

ATI Radeon HD4850 512 MB

What I have done so far to try to fix the problem:

1. Downloaded the latest Catalyst drivers from ATI.

2. Tried updating DirectX - I have the latest version anyway.

3. Tried patching Arma2 to latest version (1.09b I think)

4. Did a complete Uninstall and reinstall of the game.

I have read that Notebook with integrated graphics have this problem. But I have a good GPU and so I don't understand what else to do to fix the problem. Ideas?

[Ligr 10]

Up :(