Sounds like a symptom of bad RAM at first blush. So I'd start by grabbing a copy of memtest86+ and letting that run for a couple hours. If you start getting errors, then you'll want to test the RAM modules individually until you find the one that is defective so you can replace it.
actually i read somewhere else that it was related to Asus Suite II, and to fix it i could uninstall suites and reinstall. i just uninstalled since i never use it. that fixed the error. haven't seen it since and that was quite awhile ago