Never seen that one before but i know alot of people (including me) had troubles logging on today. All i can recommend is reinstalling minecraft and forcing update. Also i played in browser for like 5 minutes and that fixed it.
There's been problems with the login server/ skins server lately, if you see that error, wait it out.
i was getting that yesterday as well. It took almost an hour to clear. At the same time i also had trouble logging into MC.net. So it must have been slight issues with their servers.
