Problem with Hardware High Quality Lighting.

I am having problems with either rendering
in Hardware mode with High Quality Lighting turned on.
If I use Hardware Buffer Render then it renders fine but cannot save the image...
Do you have any tips for me?
Is the hardware good enough or should I have bought a FireGL Card?

Hardware Specs

AMD 4800+ X2 Dual Core
2Gb Dual DDR400
Sapphire Crossfire Express 3200 Mainboard
2x250Gb Seagate HDD SATA - RAID 0
-CROSSFIRE-
1x ATI X1900 XT 512Mb GDDR3
1x ATI X1900 XTX 512Mb GDDR3
500w PSU

With my currenct config I can render 2,500,000 Polygons in 4 sec with 30+ Samples...