Yesterday my chrome started to act strangely. On a few sites like codeschool.com it showed an error explaining that it needed the divx plugin to play videos. At first I couldn't figure out why, but than I remembered that I installed the divx webplayer a few weeks ago and directly uninstalled it.
I started to look for leftovers of that plugin. After searching for a little while I found it. Somehow the plugin was still in the chrome directory, but was not listed within chrome. Deleting its directory was the final fix for it.
rm -rf "~/Library/Application Support/Google/Chrome/Default/Google/Chrome/Default/nneajnkjbffgblleaoojgaacokifdkhm"
Never ever install the divx webplayer. It is not worth it :( .