我的版本：
E:\work\depot\script>ruby -v
ruby 1.8.5 (2006-12-25 patchlevel 12) [i386-mswin32]

E:\work\depot\script>gem -v
0.9.2

在windows下按照《agile web development with rails》往下做，结果不知道怎么就出了下面的报错，请大虾帮忙，看怎么解决，谢谢！



E:\work\depot\script>ruby server
./../config/boot.rb:29:Warning: require_gem is obsolete.  Use gem instead.
=> Booting WEBrick...
E:/ruby/lib/ruby/1.8/yaml.rb:133:in `load': syntax error on line 38, col 9: `
adapter: mysql' (ArgumentError)
        from E:/ruby/lib/ruby/1.8/yaml.rb:133:in `load'
        from E:/ruby/lib/ruby/gems/1.8/gems/rails-1.2.1/lib/initializer.rb:523:i
n `database_configuration'
        from E:/ruby/lib/ruby/gems/1.8/gems/rails-1.2.1/lib/initializer.rb:228:i
n `initialize_database'
        from E:/ruby/lib/ruby/gems/1.8/gems/rails-1.2.1/lib/initializer.rb:88:in
 `process'
        from E:/ruby/lib/ruby/gems/1.8/gems/rails-1.2.1/lib/initializer.rb:43:in
 `send'
        from E:/ruby/lib/ruby/gems/1.8/gems/rails-1.2.1/lib/initializer.rb:43:in
 `run'
        from ./../config/../config/environment.rb:13
        from E:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `ge
m_original_require'
         ... 13 levels...
        from E:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.0/lib/active_suppo
rt/dependencies.rb:496:in `require'
        from E:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.0/lib/active_suppo
rt/dependencies.rb:343:in `new_constants_in'
        from E:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.0/lib/active_suppo
rt/dependencies.rb:496:in `require'
        from server:3