Planet13 - 7:31 pm on Jul 8, 2013 (gmt 0)
I haven't watched this video yet, so maybe I shouldn't be posting it, but...
Apparently, google is treating 301 redirects from an internal page to a home page as a 404.
starting around minute 22 of the video. (Try around minute 21:30)
(sorry, internet connection at work is too slow to watch...)