For your Graphics Card...
I was having LOTS of problems, exactly the same as yours. I had downloaded DirectX9 (Beta and Public Release)...but my Graphics driver didn't support them yet. My graphics driver is from nVidia, they just released a DirectX9 compatible driver and I've not had a single error since!
Have a look on your graphic card manufacturer's website at "Driver Updates" or something along those lines. Make sure you have the latest version of your driver...if you do it's prolly not that
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