Get this error: "A copy of * has been removed from the module tree but is still active!"

Hi,

In one of my javascript functions I do two consecutive GET (ajax)
requests in quick succession. I get the following error in Rails
version 2.3.3 but not in 2.3.2. If I give a time lag (even 500ms)
between to two requests the problem vanishes!!:


ArgumentError

in StudentsController#index
A copy of StudentsController has been removed from the module
tree but is still active!

Sometimes I also get ‘A copy of AuthenticatedSystem has been removed
from the module tree but is still active!’ error.

Someone else has also been having a similar problem (http://
railsforum.com/viewtopic.php?id=33976)

The application trace is:

<div id="Application-Trace" style="display: block;">
  <pre><code>/usr/lib/ruby/gems/1.8/gems/activesupport-2.3.3/lib/

active_support/dependencies.rb:414:in load_missing_constant' /usr/lib/ruby/gems/1.8/gems/activesupport-2.3.3/lib/active_support/ dependencies.rb:96:in const_missing’
/home/~/app/controllers/students_controller.rb:4:in `index’</
pre>

<div id="Framework-Trace" style="display: none;">
  <pre><code>/usr/lib/ruby/gems/1.8/gems/activesupport-2.3.3/lib/

active_support/dependencies.rb:414:in load_missing_constant' /usr/lib/ruby/gems/1.8/gems/activesupport-2.3.3/lib/active_support/ dependencies.rb:96:in const_missing’
/usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/
base.rb:1327:in send' /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/ base.rb:1327:in perform_action_without_filters’
/usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/
filters.rb:617:in call_filters' /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/ filters.rb:610:in perform_action_without_benchmark’
/usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/
benchmarking.rb:68:in perform_action_without_rescue' /usr/lib/ruby/gems/1.8/gems/activesupport-2.3.3/lib/active_support/ core_ext/benchmark.rb:17:in ms’
/usr/lib/ruby/1.8/benchmark.rb:308:in realtime' /usr/lib/ruby/gems/1.8/gems/activesupport-2.3.3/lib/active_support/ core_ext/benchmark.rb:17:in ms’
/usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/
benchmarking.rb:68:in perform_action_without_rescue' /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/ rescue.rb:160:in perform_action_without_flash’
/usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/
flash.rb:146:in perform_action' /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/ base.rb:527:in send’
/usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/
base.rb:527:in process_without_filters' /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/ filters.rb:606:in process’
/usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/
base.rb:391:in process' /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/ base.rb:386:in call’
/usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/
routing/route_set.rb:434:in call' /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/ dispatcher.rb:88:in dispatch’
/usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/
dispatcher.rb:111:in _call' /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/ dispatcher.rb:82:in initialize’
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.3/lib/active_record/
query_cache.rb:29:in call' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.3/lib/active_record/ query_cache.rb:29:in call’
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.3/lib/active_record/
connection_adapters/abstract/query_cache.rb:34:in cache' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.3/lib/active_record/ query_cache.rb:9:in cache’
/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.3/lib/active_record/
query_cache.rb:28:in call' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.3/lib/active_record/ connection_adapters/abstract/connection_pool.rb:361:in call’
/usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/head.rb:9:in call' /usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/methodoverride.rb: 24:in call’
/usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/
params_parser.rb:15:in call' /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/ session/cookie_store.rb:93:in call’
/usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/
reloader.rb:29:in call' /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/ failsafe.rb:26:in call’
/usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in call' /usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in synchronize’
/usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in call' /usr/lib/ruby/gems/1.8/gems/actionpack-2.3.3/lib/action_controller/ dispatcher.rb:106:in call’
/usr/lib/ruby/gems/1.8/gems/rails-2.3.3/lib/rails/rack/static.rb:31:in
call' /usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:46:in call’
/usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:40:in each' /usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:40:in call’
/usr/lib/ruby/gems/1.8/gems/rails-2.3.3/lib/rails/rack/log_tailer.rb:
17:in call' /usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/content_length.rb: 13:in call’
/usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/chunked.rb:15:in
call' /usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/handler/mongrel.rb: 61:in process’
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in
process_client' /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in each’
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in
process_client' /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in run’
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in
initialize' /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in new’
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in run' /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in initialize’
/usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in new' /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in run’
/usr/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/handler/mongrel.rb:
34:in run' /usr/lib/ruby/gems/1.8/gems/rails-2.3.3/lib/commands/server.rb:111 /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require’
/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in
`require’
script/server:3