Your not overclocking are you ? (That was how I came up with these
once.) 

Make sure the chips are cool enough. Running a cpu intensive app will
help to generate lots-o-errors.

Try swapping out the ram temporarily to see if it is a little flaky...

Also see : http://lhd.datapower.com/db/dispproduct.php3?DISP?1823

and similar results of a google search....
-- 
Kevin O'Connor

She can kill all your files;
She can freeze with a frown.
And a wave of her hand brings the whole system down.
And she works on her code until ten after three.
She lives like a bat but she's always a hacker to me.
                -- Apologies to Billy Joel