node.js - ubuntu下无法从源安装nodejs

根据官方文档：

sudo apt-get update  
sudo apt-get install python-software-properties python g++ make  
sudo add-apt-repository ppa:chris-lea/node.js  
sudo apt-get update  
sudo apt-get install nodejs  

It installs current stable Node on the current stable Ubuntu. Quantal (12.10) users may need to install the software-properties-common package for the add-apt-repository command to work: sudo apt-get install software-properties-common

安装 software-properties-common 时出现 Size mismatch 错误：

Failed to fetch http://ubuntu.mirrors.ucloud.cn/ubuntu/pool/main/s/software-properties/software-properties-common_0.82.7.3_all.deb Size mismatch E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

尝试更新源（sudo apt-get update）时则出现以下错误：

Reading package lists... Done W: GPG error: http://ubuntu.mirrors.ucloud.cn precise InRelease: File /var/lib/apt/lists/partial/ubuntu.mirrors.ucloud.cnubuntudistspreciseInRelease doesn't start with a clearsigned message W: GPG error: http://ubuntu.mirrors.ucloud.cn precise-updates InRelease: File /var/lib/apt/lists/partial/ubuntu.mirrors.ucloud.cnubuntudistsprecise-updatesInRelease doesn't start with a clearsigned message W: GPG error: http://ubuntu.mirrors.ucloud.cn precise-backports InRelease: File /var/lib/apt/lists/partial/ubuntu.mirrors.ucloud.cnubuntudistsprecise-backportsInRelease doesn't start with a clearsigned message W: GPG error: http://ubuntu.mirrors.ucloud.cn precise-security InRelease: File /var/lib/apt/lists/partial/ubuntu.mirrors.ucloud.cnubuntudistsprecise-securityInRelease doesn't start with a clearsigned message

相关信息

Ubuntu 12.04 64位

求解决