500 error during new milestone creation

[tourman]

Started GET "/projects/test/milestones/new" for [IP] at 2014-10-18 16:39:25 +0300
Processing by MilestonesController#new as HTML
  Parameters: {"project_id"=>"test"}
  Current user: admin (id=1)
Completed 500 Internal Server Error in 5.8ms

NoMethodError (undefined method `id' for nil:NilClass):
  plugins/redmine_milestones/app/controllers/milestones_controller.rb:8:in `new'
  actionpack (3.2.19) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
  actionpack (3.2.19) lib/abstract_controller/base.rb:167:in `process_action'
  actionpack (3.2.19) lib/action_controller/metal/rendering.rb:10:in `process_action'
  actionpack (3.2.19) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
  activesupport (3.2.19) lib/active_support/callbacks.rb:480:in `_run__3506302918094714503__process_action__2486236489181989504__callbacks'
  activesupport (3.2.19) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.19) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
  activesupport (3.2.19) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.19) lib/abstract_controller/callbacks.rb:17:in `process_action'
  actionpack (3.2.19) lib/action_controller/metal/rescue.rb:29:in `process_action'
  actionpack (3.2.19) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
  activesupport (3.2.19) lib/active_support/notifications.rb:123:in `block in instrument'
  activesupport (3.2.19) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
  activesupport (3.2.19) lib/active_support/notifications.rb:123:in `instrument'
  actionpack (3.2.19) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
  actionpack (3.2.19) lib/action_controller/metal/params_wrapper.rb:207:in `process_action'
  activerecord (3.2.19) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
  actionpack (3.2.19) lib/abstract_controller/base.rb:121:in `process'
  actionpack (3.2.19) lib/abstract_controller/rendering.rb:45:in `process'
  actionpack (3.2.19) lib/action_controller/metal.rb:203:in `dispatch'
  actionpack (3.2.19) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
  actionpack (3.2.19) lib/action_controller/metal.rb:246:in `block in action'
  actionpack (3.2.19) lib/action_dispatch/routing/route_set.rb:73:in `call'
  actionpack (3.2.19) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
  actionpack (3.2.19) lib/action_dispatch/routing/route_set.rb:36:in `call'
  journey (1.0.4) lib/journey/router.rb:68:in `block in call'
  journey (1.0.4) lib/journey/router.rb:56:in `each'
  journey (1.0.4) lib/journey/router.rb:56:in `call'
  actionpack (3.2.19) lib/action_dispatch/routing/route_set.rb:608:in `call'
  rack-openid (1.4.2) lib/rack/openid.rb:98:in `call'
  actionpack (3.2.19) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
  rack (1.4.5) lib/rack/etag.rb:23:in `call'
  rack (1.4.5) lib/rack/conditionalget.rb:25:in `call'
  actionpack (3.2.19) lib/action_dispatch/middleware/head.rb:14:in `call'
  actionpack (3.2.19) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
  actionpack (3.2.19) lib/action_dispatch/middleware/flash.rb:242:in `call'
  rack (1.4.5) lib/rack/session/abstract/id.rb:210:in `context'
  rack (1.4.5) lib/rack/session/abstract/id.rb:205:in `call'
  actionpack (3.2.19) lib/action_dispatch/middleware/cookies.rb:341:in `call'
  activerecord (3.2.19) lib/active_record/query_cache.rb:64:in `call'
  activerecord (3.2.19) lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call'
  actionpack (3.2.19) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
  activesupport (3.2.19) lib/active_support/callbacks.rb:405:in `_run__4258006750504848907__call__634116511619353909__callbacks'
  activesupport (3.2.19) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.19) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
  activesupport (3.2.19) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.19) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
  actionpack (3.2.19) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
  actionpack (3.2.19) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
  actionpack (3.2.19) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
  railties (3.2.19) lib/rails/rack/logger.rb:32:in `call_app'
  railties (3.2.19) lib/rails/rack/logger.rb:16:in `block in call'
  activesupport (3.2.19) lib/active_support/tagged_logging.rb:22:in `tagged'
  railties (3.2.19) lib/rails/rack/logger.rb:16:in `call'
  actionpack (3.2.19) lib/action_dispatch/middleware/request_id.rb:22:in `call'
  rack (1.4.5) lib/rack/methodoverride.rb:21:in `call'
  rack (1.4.5) lib/rack/runtime.rb:17:in `call'
  activesupport (3.2.19) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
  rack (1.4.5) lib/rack/lock.rb:15:in `call'
  actionpack (3.2.19) lib/action_dispatch/middleware/static.rb:63:in `call'
  rack-cache (1.2) lib/rack/cache/context.rb:136:in `forward'
  rack-cache (1.2) lib/rack/cache/context.rb:245:in `fetch'
  rack-cache (1.2) lib/rack/cache/context.rb:185:in `lookup'
  rack-cache (1.2) lib/rack/cache/context.rb:66:in `call!'
  rack-cache (1.2) lib/rack/cache/context.rb:51:in `call'
  railties (3.2.19) lib/rails/engine.rb:484:in `call'
  railties (3.2.19) lib/rails/application.rb:231:in `call'
  railties (3.2.19) lib/rails/railtie/configurable.rb:30:in `method_missing'
  rack (1.4.5) lib/rack/urlmap.rb:64:in `block in call'
  rack (1.4.5) lib/rack/urlmap.rb:49:in `each'
  rack (1.4.5) lib/rack/urlmap.rb:49:in `call'
  thin (1.6.2) lib/thin/connection.rb:86:in `block in pre_process'
  thin (1.6.2) lib/thin/connection.rb:84:in `catch'
  thin (1.6.2) lib/thin/connection.rb:84:in `pre_process'
  thin (1.6.2) lib/thin/connection.rb:53:in `process'
  thin (1.6.2) lib/thin/connection.rb:39:in `receive_data'
  eventmachine (1.0.3) lib/eventmachine.rb:187:in `run_machine'
  eventmachine (1.0.3) lib/eventmachine.rb:187:in `run'
  thin (1.6.2) lib/thin/backends/base.rb:73:in `start'
  thin (1.6.2) lib/thin/server.rb:162:in `start'
  thin (1.6.2) lib/thin/controllers/controller.rb:87:in `start'
  thin (1.6.2) lib/thin/runner.rb:199:in `run_command'
  thin (1.6.2) lib/thin/runner.rb:155:in `run!'
  thin (1.6.2) bin/thin:6:in `<top (required)>'
  /usr/local/bin/thin:23:in `load'
  /usr/local/bin/thin:23:in `<main>'

Environment:
  Redmine version                2.5.2.stable
  Ruby version                   2.1.0-p0 (2013-12-25) [x86_64-linux]
  Rails version                  3.2.19
  Environment                    production
  Database adapter               Mysql2
SCM:
  Subversion                     1.6.11
  Git                            1.7.1
  Filesystem                     
Redmine plugins:
  redmine_milestones             1.0.0-pro-alpha1

[gregoo]

(A bit late but...)

Hello, while initializing, the controller depends on your project versions.

  def new
    @milestone = Milestone.new
    session[:version_id] = @project.versions.first.id
  end

If you have no version in your project, @project.versions is empty, @project.versions.first is nil and @project.versions.first.id does not exist.

Create a version in your project to fix the error. The versions are located on a tab like the milestones are when you configure your project (-: