Redmine

If I try to start redmine 0.9.3 with Taskjuggler-Plugin
it doesn't work and I get the error below:

I didn't try it with older versions but I would like to try this plugin.

Can somebody give me a hand with that?

Error Output:

/home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:426:in `load_missing_constant': Expected /home/dani/Downloads/redmine-0.9/app/models/user.rb to define User (LoadError)
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:80:in `const_missing'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:92:in `const_missing'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:437:in `load_missing_constant'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:96:in `const_missing'
    from /home/dani/Downloads/redmine-0.9/app/models/project.rb:25
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:158:in `require'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:265:in `require_or_load'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:425:in `load_missing_constant'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:80:in `const_missing'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:92:in `const_missing'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:437:in `load_missing_constant'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:96:in `const_missing'
    from /home/dani/Downloads/redmine-0.9/app/models/principal.rb:22
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:158:in `require'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:265:in `require_or_load'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:425:in `load_missing_constant'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:80:in `const_missing'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:92:in `const_missing'
    from /home/dani/Downloads/redmine-0.9/app/models/user.rb:20
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:158:in `require'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:265:in `require_or_load'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:224:in `depend_on'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:136:in `require_dependency'
    from /home/dani/Downloads/redmine-0.9/vendor/plugins/redmine_taskjuggler/lib/issue_patch.rb:1
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:158:in `require'
    from /home/dani/Downloads/redmine-0.9/vendor/plugins/redmine_taskjuggler/init.rb:5:in `evaluate_init_rb'
    from /home/dani/.gem/ruby/1.8/gems/rails-2.3.5/lib/rails/plugin.rb:158:in `evaluate_init_rb'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/core_ext/kernel/reporting.rb:11:in `silence_warnings'
    from /home/dani/.gem/ruby/1.8/gems/rails-2.3.5/lib/rails/plugin.rb:154:in `evaluate_init_rb'
    from /home/dani/.gem/ruby/1.8/gems/rails-2.3.5/lib/rails/plugin.rb:48:in `load'
    from /home/dani/Downloads/redmine-0.9/config/../vendor/plugins/engines/lib/engines/plugin.rb:44:in `load'
    from /home/dani/.gem/ruby/1.8/gems/rails-2.3.5/lib/rails/plugin/loader.rb:38:in `load_plugins'
    from /home/dani/.gem/ruby/1.8/gems/rails-2.3.5/lib/rails/plugin/loader.rb:37:in `each'
    from /home/dani/.gem/ruby/1.8/gems/rails-2.3.5/lib/rails/plugin/loader.rb:37:in `load_plugins'
    from /home/dani/.gem/ruby/1.8/gems/rails-2.3.5/lib/initializer.rb:369:in `load_plugins'
    from /home/dani/.gem/ruby/1.8/gems/rails-2.3.5/lib/initializer.rb:165:in `process'
    from /home/dani/.gem/ruby/1.8/gems/rails-2.3.5/lib/initializer.rb:113:in `send'
    from /home/dani/.gem/ruby/1.8/gems/rails-2.3.5/lib/initializer.rb:113:in `run'
    from /home/dani/Downloads/redmine-0.9/config/environment.rb:20
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:521:in `new_constants_in'
    from /home/dani/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
    from /home/dani/.gem/ruby/1.8/gems/rails-2.3.5/lib/commands/server.rb:84
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
    from script/server:3