while trying to upgrade to 12.10 got the msg:
Failed to download repository information.Check your Internet connection.Pinging twocows.com works.
marked as duplicate by Rinzwind, green7, LnxSlck, Jorge Castro, hhlp Nov 20 '12 at 18:17
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
Just because you can reach twocows.com, it doesn't mean you can get the repository your system is expecting.
There are a few things that might be the case: