ruby删除了原来的ruby源更新成淘宝的出错

删除原来的ruby源 要想用淘宝的结果就报错，望大神解救
gem source -a http://ruby.taobao.org
/usr/local/ruby-1.8/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:in gem_original_require': no such file to load -- zlib (LoadError)
from /usr/local/ruby-1.8/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:inrequire'
from /usr/local/ruby-1.8/lib/ruby/site_ruby/1.8/rubygems.rb:540:in gunzip'
from /usr/local/ruby-1.8/lib/ruby/site_ruby/1.8/rubygems/remote_fetcher.rb:239:infetch_path'
from /usr/local/ruby-1.8/lib/ruby/site_ruby/1.8/rubygems/spec_fetcher.rb:269:in load_specs'
from /usr/local/ruby-1.8/lib/ruby/site_ruby/1.8/rubygems/commands/sources_command.rb:72:inexecute'
from /usr/local/ruby-1.8/lib/ruby/site_ruby/1.8/rubygems/command.rb:278:in invoke'
from /usr/local/ruby-1.8/lib/ruby/site_ruby/1.8/rubygems/command_manager.rb:147:inprocess_args'
from /usr/local/ruby-1.8/lib/ruby/site_ruby/1.8/rubygems/command_manager.rb:117:in run'
from /usr/local/ruby-1.8/lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb:65:inrun'
from /usr/local/ruby-1.8/bin/gem:30

图片打不开，不过ruby环境配置可以参考下。
http://blog.csdn.net/u013346305/article/details/47260159