Ubuntu 下配置Ruby1.9.1,Rails2.3.3出错

安装一切正常
ruby -v; gem -v; rails -v都能出来正确的结果。

但用rails project时，就出错了，错误原因

$ rails hello
/usr/local/ruby/lib/ruby/gems/1.9.1/gems/rails-2.3.3/lib/rails_generator/options.rb:32:in default_options': [b][color=red]undefined methodwrite_inheritable_attribute' for Rails::Generator::Base:Class (NoMethodError)[/color][/b］
from /usr/local/ruby/lib/ruby/gems/1.9.1/gems/rails-2.3.3/lib/rails_generator/base.rb:90:in <class:Base>'
from /usr/local/ruby/lib/ruby/gems/1.9.1/gems/rails-2.3.3/lib/rails_generator/base.rb:85:inmodule:Generator'
from /usr/local/ruby/lib/ruby/gems/1.9.1/gems/rails-2.3.3/lib/rails_generator/base.rb:48:in <module:Rails>'
from /usr/local/ruby/lib/ruby/gems/1.9.1/gems/rails-2.3.3/lib/rails_generator/base.rb:6:in'
from /usr/local/ruby/lib/ruby/gems/1.9.1/gems/rails-2.3.3/lib/rails_generator.rb:34:in require'
from /usr/local/ruby/lib/ruby/gems/1.9.1/gems/rails-2.3.3/lib/rails_generator.rb:34:in'
from /usr/local/ruby/lib/ruby/gems/1.9.1/gems/rails-2.3.3/bin/rails:14:in require'
from /usr/local/ruby/lib/ruby/gems/1.9.1/gems/rails-2.3.3/bin/rails:14:in'
from /usr/local/ruby/bin/rails:19:in load'
from /usr/local/ruby/bin/rails:19:in'

有很多关于这个问题的分析，全是英文 ，大意是[color=red]iconv.so未配置好[/color]，已经一周了。实在搞不定，谁有办法，帮我一下啊。。第一次配环境。
[b]问题补充：[/b]
感谢night_stalker的回答，按你的提示，我去试了下

[code="sh"］require 'iconv'
返回
[color=red]=> true[/color][/code]

[code="java"]
sudo apt-get install iconv
[color=red]E: Couldn't find package iconv[/color]
[/code]

我试着用了你的 iconv-pure 后，还是不行，错误原因一样！
[b]问题补充：[/b]
[code="java"]
irb(main):001:0> require 'activesupport'

LoadError: no such file to load -- activesupport
from (irb):1:in require'
from (irb):1
from /usr/local/ruby/bin/irb:12:in'
[/code]

看来应该是这个问题了，我先自己找下解决方案，麻烦你也帮我看下怎么解决吧。
谢谢了！ :D
[b]问题补充：[/b]
再次感谢 night_stalker：

问题解决了，果然是activesupport引起的。
我运行了这个gem去安装
[code="java"]
$ sudo gem install activesupport
[/code]

安装完成后就好了，谢谢！