Unable to update using apt-get or GUI

I just reflashed my Nexus7 with the 13.04 image and I am no longer able to get updates form the command line using apt-get or with the GUI. In either case I get the following error/waring messages:

W: Failed to fetch http://ppa.launchpad.net/ubuntu-nexus7/ppa/ubuntu/dists/raring/main/source/Sources 404 Not Found

W: Failed to fetch http://ppa.launchpad.net/ubuntu-nexus7/ppa/ubuntu/dists/raring/main/binary-armhf/Packages 404 Not Found

W: Failed to fetch bzip2:/var/lib/apt/lists/partial/ports.ubuntu.com_ubuntu-ports_dists_raring_main_source_Sources Hash Sum mismatch

W: Failed to fetch bzip2:/var/lib/apt/lists/partial/ports.ubuntu.com_ubuntu-ports_dists_raring_universe_source_Sources Hash Sum mismatch

E: Some index files failed to download. They have been ignored, or old ones used instead.

I've been able to download applications using the Ubuntu Software Center so network connectivity is there.

Any ideas?