That's very odd, I have almost the same settings with my Asus M2N32 SLI, X2 4600+, 2GB Corsair 6400C4. I have also OC'd to 217 FSB and system is very stable for a week now:
FSB: 217
Multiplier: 12X
CPU voltage: 1.392V
HTT: 5X
RAM speed: 866MHz (800 divider)
RAM voltage:2.0V (default)...