Redmine

I get internal server error on every issue creation/update. When creating/updating issue, this is from the log:

Processing IssuesController#new (for 89.216.115.50 at 2010-04-21 10:05:24) [POST]
  Parameters: {"commit"=>"Create", "project_id"=>"epermit", "action"=>"new", "authenticity_token"=>"4FAiBNDmMajWE9w40LQIqdEAMtCmh+lwDoWEp7+JUTc=", "issue"=>{"start_date"=>"2010-04-21", "estimated_hours"=>"", "priority_id"=>"4", "done_ratio"=>"0", "assigned_to_id"=>"3", "subject"=>"Test issue", "tracker_id"=>"1", "due_date"=>"", "status_id"=>"1", "description"=>"Testing it."}, "controller"=>"issues", "attachments"=>{"1"=>{"description"=>""}}}
Redirected to http://dev.etondigital.com:3000/issues/7
Completed in 113ms (DB: 24) | 302 Found [http://XXX/projects/epermit/issues/new]

And it displays Internal error. When I click on back, the issue is created regardless of the error.

While updating issue, the same happens, only I get this after clicking Back on the error page:

/!\ FAILSAFE /!\  Wed Apr 21 10:06:57 +0200 2010
  Status: 500 Internal Server Error
  undefined method `merge' for nil:NilClass
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/request.rb:385:in `parameters'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/base.rb:1288:in `assign_shortcuts'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/base.rb:527:in `process_without_filters'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/filters.rb:606:in `process'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/rescue.rb:65:in `call_with_exception'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/dispatcher.rb:90:in `dispatch'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/dispatcher.rb:121:in `_call'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/dispatcher.rb:130:in `build_middleware_stack'
    /opt/redmine-0.9.3/vendor/rails/activerecord/lib/active_record/query_cache.rb:29:in `call'
    /opt/redmine-0.9.3/vendor/rails/activerecord/lib/active_record/query_cache.rb:29:in `call'
    /opt/redmine-0.9.3/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache'
    /opt/redmine-0.9.3/vendor/rails/activerecord/lib/active_record/query_cache.rb:9:in `cache'
    /opt/redmine-0.9.3/vendor/rails/activerecord/lib/active_record/query_cache.rb:28:in `call'
    /opt/redmine-0.9.3/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb:361:in `call'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/string_coercion.rb:25:in `call'
    /usr/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/head.rb:9:in `call'
    /usr/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/methodoverride.rb:24:in `call'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/params_parser.rb:15:in `call'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/session/cookie_store.rb:93:in `call'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/failsafe.rb:26:in `call'
    /usr/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/lock.rb:11:in `call'
    /usr/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/lock.rb:11:in `synchronize'
    /usr/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/lock.rb:11:in `call'
    /opt/redmine-0.9.3/vendor/rails/actionpack/lib/action_controller/dispatcher.rb:106:in `call'
    /opt/redmine-0.9.3/vendor/rails/railties/lib/rails/rack/static.rb:31:in `call'
    /usr/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb:46:in `call'
    /usr/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb:40:in `each'
    /usr/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb:40:in `call'
    /opt/redmine-0.9.3/vendor/rails/railties/lib/rails/rack/log_tailer.rb:17:in `call'
    /usr/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/content_length.rb:13:in `call'
    /usr/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/handler/webrick.rb:50:in `service'
    /usr/lib/ruby/1.8/webrick/httpserver.rb:104:in `service'
    /usr/lib/ruby/1.8/webrick/httpserver.rb:65:in `run'
    /usr/lib/ruby/1.8/webrick/server.rb:173:in `start_thread'
    /usr/lib/ruby/1.8/webrick/server.rb:162:in `start'
    /usr/lib/ruby/1.8/webrick/server.rb:162:in `start_thread'
    /usr/lib/ruby/1.8/webrick/server.rb:95:in `start'
    /usr/lib/ruby/1.8/webrick/server.rb:92:in `each'
    /usr/lib/ruby/1.8/webrick/server.rb:92:in `start'
    /usr/lib/ruby/1.8/webrick/server.rb:23:in `start'
    /usr/lib/ruby/1.8/webrick/server.rb:82:in `start'
    /usr/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/handler/webrick.rb:14:in `run'
    /opt/redmine-0.9.3/vendor/rails/railties/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

This is the environment:

$ ruby script/about
./script/../config/../vendor/rails/railties/lib/rails/gem_dependency.rb:119:Warning: Gem::Dependency#version_requirements is deprecated and will be removed on or after August 2010.  Use #requirement
About your application's environment
Ruby version              1.8.7 (x86_64-linux)
RubyGems version          1.3.6
Rack version              1.0
Rails version             2.3.5
Active Record version     2.3.5
Active Resource version   2.3.5
Action Mailer version     2.3.5
Active Support version    2.3.5
Edge Rails revision       unknown
Application root          /opt/redmine-0.9.3
Environment               development
Database adapter          mysql
Database schema version   20100221100219

Please help, I have no idea why this happens (and googling doesnt help). Thanks!