12.04 - Failing to fetch some packages in update

I want to get ruby on rails on ubuntu 12.04 but I'm coming across errors that say I need to to update. I've copied the result of the end of update and not included the earlier part. I can add that if it is needed.

Hit http://us.archive.ubuntu.com precise-backports/restricted Translation-en
Hit http://us.archive.ubuntu.com precise-backports/universe Translation-en
Fetched 2,916 kB in 4s (663 kB/s)
W: Failed to fetch http://ppa.launchpad.net/gijzelaar/opencv2/ubuntu/dists/precise/main/source/Sources  404  Not Found

W: Failed to fetch http://ppa.launchpad.net/gijzelaar/opencv2/ubuntu/dists/precise/main/binary-amd64/Packages  404  Not Found

W: Failed to fetch http://ppa.launchpad.net/gijzelaar/opencv2/ubuntu/dists/precise/main/binary-i386/Packages  404  Not Found


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

When I run rvm requirements this is the error I'm seeing.

Checking requirements for ubuntu.
Installing requirements for ubuntu.
Updating system..................
Error running 'requirements_debian_update_system ',
showing last 15 lines of /home/charles/.rvm/log/1397254493/update_system.log

+ case "${TERM:-dumb}" in
+ case "$1" in
+ [[ -t 2 ]]
+ return 1
+ printf %b 'There has been error while updating '\''apt-get'\'', please give it some time and try again later.
For 404 errors check your sources configured in:
    /etc/apt/sources.list
    /etc/apt/sources.list.d/*.list
\n'
There has been error while updating 'apt-get', please give it some time and try again later.

For 404 errors check your sources configured in:
    /etc/apt/sources.list
    /etc/apt/sources.list.d/*.list

+ return 100
Requirements installation failed with status: 100.

I'm following the instructions from
https://www.digitalocean.com/community/articles/how-to-install-ruby-on-rails-on-ubuntu-12-04-lts-precise-pangolin-with-rvm

This PPA was renamed at some point, and might actually be an issue with Launchpad. It's possible that browser hits redirect but files do not.

Currently, the "opencv2" repo redirects to "opencv2.2". 2.4 is actually more current. If you wanted 2.2, it's possible the repo is "dead" because of this. This will install 2.4.

• Remove the PPA

sudo apt-add-repository --remove ppa:gijzelaar/opencv2

• Install the direct PPA

sudo apt-add-repository ppa:gijzelaar/opencv2.4 -y

• Update your sources

sudo apt-get update

• Retry your command.