Your GTX 580 has shader model 5.0.
That site is incorrect.
D3D error is to do with your directx runtime libraries.
With your install disc for your game go into the disc and find the directx setup and install from there.
I went onto both discs and found it on the second disc, but it wouldn't let me install because it said I needed; D:\Data.z01
then right after I get a winrar error.
The first disc had that a file named Data.z01 and also Data.cd but I couldnt open them