如何修复Rails安装错误?

我刚刚在我的Ubuntu系统上安装了Ruby on Rails所需的一切。 但是,当我使用rails命令时,它会输出以下错误:

 root@laptop3:/var/lib/gems/1.8/specifications# rails -v Invalid gemspec in [/var/lib/gems/1.8/specifications/activemodel-3.2.0.gemspec]: Illformed requirement ["# 3.2.0"] Invalid gemspec in [/var/lib/gems/1.8/specifications/activerecord-3.2.0.gemspec]: Illformed requirement ["# 3.2.0"] Invalid gemspec in [/var/lib/gems/1.8/specifications/activeresource-3.2.0.gemspec]: Illformed requirement ["# 3.2.0"] Invalid gemspec in [/var/lib/gems/1.8/specifications/actionpack-3.2.0.gemspec]: Illformed requirement ["# 3.2.0"] Invalid gemspec in [/var/lib/gems/1.8/specifications/railties-3.2.0.gemspec]: Illformed requirement ["# 3.2.0"] Invalid gemspec in [/var/lib/gems/1.8/specifications/actionmailer-3.2.0.gemspec]: Illformed requirement ["# 3.2.0"] Invalid gemspec in [/var/lib/gems/1.8/specifications/tilt-1.3.3.gemspec]: invalid date format in specification: "2011-08-25 00:00:00.000000000Z" Invalid gemspec in [/var/lib/gems/1.8/specifications/rails-3.2.0.gemspec]: Illformed requirement ["# 3.2.0"] /usr/lib/ruby/vendor_ruby/1.8/rubygems.rb:926:in `report_activate_error': Could not find RubyGem railties (>= 0) (Gem::LoadError) from /usr/lib/ruby/vendor_ruby/1.8/rubygems.rb:244:in `activate_dep' from /usr/lib/ruby/vendor_ruby/1.8/rubygems.rb:236:in `activate' from /usr/lib/ruby/vendor_ruby/1.8/rubygems.rb:1307:in `gem' from /usr/local/bin/rails:18 

我该如何解决?

我建议使用版本管理器(如RVM)而不是发行版Ruby来安装Ruby + Ruby Gems: http : //ryanbigg.com/2010/12/ubuntu-ruby-rvm-rails-and-you/