During the "Preparation to upgrade" all is going well then I get;

Failed to fetch archive.ubuntu.com/ubuntu/dists/feisty/Release
Unable to find expected entry main'./binary-i386/Packages in
Meta-index file (malformed Release file?)

New to Linux and have no idea as to where to go, my system running
7.04 is up to date and internet connection is good.

Any help?