This error complains about a failed package list refresh or an old package list. Try to update the list either via some ApplicationManager or via pure 'apt-get update' .
If this fails, this is always a connection issue, either on your side, or most likely on the repository server side. There are slim chances that using skeiron.org mirror may work better, but sometimes your only chance is to wait for the repositories to be connect-able for you again.