I just got the game today and i'm having the same alpha blending error. however, i checked the supported chipset list on the back of the box and my Radeon 9600 Pro was on there. I have a home built Athlon 64 3200 system on an Asus K8V-SE Delux board so i didn't think it was a hardware issue (but very easily could be wrong).
I tried to install stuff from ATI's website but probabily did more harm than good. I'm now at a loss of what to do. If anyone has any suggestions i'd greatly appreciate it! If you need any more specs just let me know. Happy holidays.