I don't know if you can ignore the errors or not. When I get errors I fix it- that's how I roll, and it's what I recommend you to do for the sake of your investment. It's possible that Vista could have a hand in it, I dunno. 3.2 is a decent jump from stock speeds though and your system probably just needs a boost in voltages somewhere.
We've established that your system runs fine at stock speeds, and we've eliminated memory as the culprit here. I would raise North Bridge voltage in the smallest increments allowed. It's probably going to be somewhat time consuming, but start at the lowest voltage available when leaving auto and work your way up until you achieve stability.
BTW this is a little guide using an ASUS board that you might find helpful. http://www.digital-daily.com/motherboard/asus_p5b_deluxe_wifi/index05.htm
If you fix the problem please chime in and let us know what worked.