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