Ruby on Rails application could not be started

These are the possible causes:
  • There may be a syntax error in the application's code. Please check for such errors and fix them.
  • A required library may not installed. Please install all libraries that this application requires.
  • The application may not be properly configured. Please check whether all configuration files are written correctly, fix any incorrect configurations, and restart this application.
  • A service that the application relies on (such as the database server or the Ferret search engine server) may not have been started. Please start that service.
Further information about the error may have been written to the application's log file. Please check it in order to analyse the problem.
Error message:
can't activate actionpack (= 1.13.6, runtime), already activated actionpack-2.0.2
Exception class:
Gem::Exception
Application root:
/var/kunden/webs/monsta/schule-als-staat.org/www
Backtrace:
# File Line Location
0 /usr/local/lib/site_ruby/1.8/rubygems.rb 142 in `activate'
1 /usr/local/lib/site_ruby/1.8/rubygems.rb 158 in `activate'
2 /usr/local/lib/site_ruby/1.8/rubygems.rb 157 in `each'
3 /usr/local/lib/site_ruby/1.8/rubygems.rb 157 in `activate'
4 /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb 31 in `require'
5 /usr/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb 496 in `require'
6 /usr/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb 342 in `new_constants_in'
7 /usr/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb 496 in `require'
8 ./config/environment.rb 50
9 /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb 27 in `gem_original_require'
10 /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb 27 in `require'
11 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/railz/application_spawner.rb 252 in `preload_application'
12 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/railz/application_spawner.rb 212 in `initialize_server'
13 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/utils.rb 181 in `report_app_init_status'
14 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/railz/application_spawner.rb 201 in `initialize_server'
15 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/abstract_server.rb 166 in `start_synchronously'
16 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/abstract_server.rb 135 in `start'
17 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/abstract_server.rb 112 in `fork'
18 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/abstract_server.rb 112 in `start'
19 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/railz/application_spawner.rb 177 in `start'
20 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/spawn_manager.rb 224 in `spawn_rails_application'
21 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/spawn_manager.rb 219 in `synchronize'
22 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/spawn_manager.rb 219 in `spawn_rails_application'
23 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/spawn_manager.rb 122 in `spawn_application'
24 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/spawn_manager.rb 253 in `handle_spawn_application'
25 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/abstract_server.rb 317 in `__send__'
26 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/abstract_server.rb 317 in `main_loop'
27 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/lib/passenger/abstract_server.rb 168 in `start_synchronously'
28 /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/bin/passenger-spawn-server 46