如何在Ubuntu 12.04上正确安装ruby 2.0.0？

我已经成功安装了rvm，但是当我运行以下命令时

sudo apt-get update

要么：

rvm install 2.0.0

我有以下错误：

W: Failed to fetch http://ppa.launchpad.net/cheleb/blender-svn/ubuntu/dists/precise/main/source/Sources  404  Not Found

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

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

W: Failed to fetch http://ppa.launchpad.net/ferramroberto/oneiric/ubuntu/dists/precise/main/source/Sources  404  Not Found

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

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

如何修复这些错误？

请按照以下步骤操作

sudo apt-get -y update
sudo apt-get -y install build-essential zlib1g-dev libssl-dev libreadline6-dev libyaml-dev
cd /tmp
wget http://cache.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-p481.tar.gz
tar -xvzf ruby-2.0.0-p481.tar.gz
cd ruby-2.0.0-p481/
./configure --prefix=/usr/local
make
sudo make install