运行rails应用程序服务器失败 - YAML解析器？

Question

  

可能重复：
  rails error, couldn't parse YAML

我正在尝试将一个rails项目从rails 2升级到3 我该如何解决这个问题？ 这是我需要安装的一些YAML解析器吗？

=> Booting WEBrick
=> Rails 3.1.1 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/Users/orange/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych.rb:148:in `parse': couldn't parse YAML at line 7 column 0 (Psych::SyntaxError)
        from /Users/orange/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych.rb:148:in `parse_stream'
        from /Users/orange/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych.rb:119:in `parse'

提前谢谢