Rails 1.2.1

gem update -y railsで更新しようとしたら、

Updating installed gems...
ERROR: While executing gem ... (NoMethodError)
undefined method `refresh' for #

てな感じでエラーが出て、updateできなかった。
どうやら、/usr/local/lib/ruby/gems/1.8/source_cacheを消すといいらしい。

gem update -y rails
Updating installed gems...
Bulk updating Gem source index for: http://gems.rubyforge.org
Attempting remote update of rails
Successfully installed rails-1.2.1
Successfully installed activesupport-1.4.0
Successfully installed activerecord-1.15.1
Successfully installed actionpack-1.13.1
Successfully installed actionmailer-1.3.1
Successfully installed actionwebservice-1.2.1
Installing ri documentation for activesupport-1.4.0...
Installing ri documentation for activerecord-1.15.1...
Installing ri documentation for actionpack-1.13.1...
Installing ri documentation for actionmailer-1.3.1...
Installing ri documentation for actionwebservice-1.2.1...
Installing RDoc documentation for activesupport-1.4.0...
Installing RDoc documentation for activerecord-1.15.1...
Installing RDoc documentation for actionpack-1.13.1...
Installing RDoc documentation for actionmailer-1.3.1...
Installing RDoc documentation for actionwebservice-1.2.1...
Gems: [rails] updated