Railsで原因不明のエラー。。。

Railsのデバッガを使うきっかけになったのが、原因不明のエラー。。。
サーバ起動して1回目は普通にページ遷移できるのに、2回目以降は
"そんなメソッドはねぇ。" と言われてエラー画面。

デバッガ使ってみたら1回目の正常に表示されるときの最後にこんなエラーが↓

Processing ApplicationController#index (for 192.168.1.77 at 2009-03-05 18:51:01) [GET]
2009-03-05 18:51:01: Error calling Dispatcher.dispatch #
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:422:in `remove_const'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:422:in `send'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:422:in `remove_constant'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:273:in `remove_unloadable_constants!'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:273:in `each'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:273:in `remove_unloadable_constants!'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:72:in `clear'
/usr/local/profiling/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/dispatcher.rb:60:in `reset_application!'
/usr/local/profiling/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/dispatcher.rb:116:in `reset_after_dispatch'
/usr/local/profiling/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/dispatcher.rb:51:in `dispatch'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/rails.rb:76:in `process'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/rails.rb:74:in `synchronize'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/rails.rb:74:in `process'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run'
/usr/local/profiling/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:488:in `load'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:488:in `load'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:342:in `new_constants_in'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:488:in `load'
/usr/local/profiling/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/commands/servers/mongrel.rb:60
/usr/local/profiling/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
/usr/local/profiling/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `require'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:495:in `require'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:342:in `new_constants_in'
/usr/local/profiling/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:495:in `require'
/usr/local/profiling/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/commands/server.rb:39
/usr/local/profiling/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
/usr/local/profiling/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `require'
script/server:3

これのせいで2回目以降の処理が失敗してるとか？
activesupportのバージョン上げてみるとかどう？（←安易。。。）

ググってもあんまり情報ないし。。。
http://www.ruby-forum.com/topic/119930

実はmongrelのバグとか？
主に作ってた人が今すでにいないのでmongrelで動かしてたか実績は不明。。。
明日CGIで動かしてみよう。