I used to get this. Maybe you should try Hazard's distribution of Snow Leopard. It has good AMD support. Also if it doesn't work at first, keep trying with different possibilities.

---

SportsGuy
Dell Studio Desktop 540
Intel Core 2 Quad 2.83 GHz Q9550 (All cores work)
EVGA nVidia GeForce 9500 GT (1GB) (Works)
M-Audio Fast Track Ultra Sound (Works)
Realtek Ethernet (Works)
8 GB DDR2 RAM (Of course works)
24" Dell 1920x1080 16:9 Monitor
Tri Boot with Snow Leopard 10.6.3 (64-bit) and Vista (64-bit) and Linux Mint