auraoflight - 6:08 am on Feb 2, 2012 (gmt 0)
Unfortunately, I don't think it's a technical error. I keep an almost obsessive log of everything I change on my site.
I did, however, just notice that my main page had somehow lost its meta description, keywords and also the H1 tag due to some kind of Wordpress error. I don't know how long it's been that way, though. I would be surprised if something simple as that would cause side-wide penalty.