Redmine

Internal server error when copying issues. Currently I am using in two places on both Redmine and the problem is the same.

After pressing the icon copying error window pops up.
The data file production.log are as follows:

Started GET "/redmine/issues/282" for 212.14.28.115 at 2015-11-12 00:19:00 +0100
Processing by IssuesController#show as HTML
Parameters: {"id"=>"282"}
Current user: seweryn (id=10)
Rendered issues/_action_menu.html.erb (14.4ms)
Rendered plugins/scrum/app/views/scrum_hooks/issues/_show.html.erb (7.6ms)
Rendered plugins/redmine_issue_checklist/app/views/issue_checklists/_checklist_item.html.erb (4.3ms)
Rendered plugins/redmine_issue_checklist/app/views/issue_checklists/_checklist_item.html.erb (4.7ms)
Rendered plugins/redmine_issue_checklist/app/views/issue_checklists/_checklist_item.html.erb (4.6ms)
Rendered plugins/redmine_issue_checklist/app/views/issues/_checklist.html.erb (27.2ms)
Rendered issue_relations/_form.html.erb (7.0ms)
Rendered issues/_relations.html.erb (10.7ms)
Rendered issues/_action_menu.html.erb (12.8ms)
Rendered issues/_form_custom_fields.html.erb (3.5ms)
Rendered issues/_attributes.html.erb (90.0ms)
Rendered plugins/redmine_issue_checklist/app/views/issues/_checklist_form.html.erb (4.0ms)
Rendered plugins/scrum/app/views/scrum_hooks/issues/_form.html.erb (17.1ms)
Rendered issues/_form.html.erb (178.2ms)
Rendered attachments/_form.html.erb (10.6ms)
Rendered issues/_edit.html.erb (232.1ms)
Rendered plugins/redmine_agile/app/views/agile_boards/_issues_sidebar.html.erb (9.9ms)
Rendered plugins/redmine_agile/app/views/agile_charts/_agile_charts.html.erb (2.2ms)
Rendered plugins/redmine_tagging/app/views/tagging/_tagcloud.erb (16.8ms)
Rendered issues/_sidebar.html.erb (43.4ms)
Rendered watchers/_watchers.html.erb (13.8ms)
Rendered issues/show.html.erb within layouts/base (485.0ms)
Rendered plugins/scrum/app/views/scrum_hooks/_head.html.erb (1.2ms)
Rendered plugins/scrum/app/views/scrum_hooks/_scrum_tips.html.erb (330.4ms)
Completed 200 OK in 1175ms (Views: 904.4ms | ActiveRecord: 45.5ms)
Started GET "/redmine/projects/developerv/issues/282/copy" for 212.14.28.115 at 2015-11-12 00:19:04 +0100
Processing by IssuesController#new as HTML
Parameters: {"project_id"=>"developerv", "copy_from"=>"282"}
Current user: seweryn (id=10)
Completed 500 Internal Server Error in 35ms (ActiveRecord: 2.1ms)

NoMethodError (undefined method `identifier' for nil:NilClass):
app/controllers/issues_controller.rb:409:in `build_new_issue_from_params'
lib/redmine/sudo_mode.rb:63:in `sudo_mode'

The following information data from two servers:

Server #1:
Environment:
Redmine version 3.1.1.stable.14855
Ruby version 1.9.3-p551 (2014-11-13) [i486-linux]
Rails version 4.2.4
Environment production
Database adapter Mysql2
SCM:
Subversion 1.6.6
Darcs 2.3.0
Mercurial 1.4.3
Cvs 1.12.13
Bazaar 2.1.4
Git 1.7.0.4
Filesystem
Redmine plugins:
redmine_agile 1.3.12
redmine_ckeditor 1.1.2
redmine_issue_checklist 2.0.8
redmine_lightbox2 0.2.2
redmine_tagging 0.1.3
redmine_theme_changer 0.2.0
scrum 0.13.1

Server #2:
Environment:
Redmine version 3.1.1.stable.14855
Ruby version 2.2.0-p0 (2014-12-25) [x86_64-linux]
Rails version 4.2.4
Environment production
Database adapter Mysql2
SCM:
Subversion 1.8.8
Darcs 2.8.4
Mercurial 2.8.2
Cvs 1.12.13
Bazaar 2.7.0
Git 1.9.2
Filesystem
Redmine plugins:
redmine_agile 1.3.12
redmine_ckeditor 1.1.2
redmine_custom_workflows 0.1.0
redmine_issue_checklist 2.0.8
redmine_lightbox2 0.2.2
redmine_tagging 0.1.3
redmine_theme_changer 0.2.0
scrum 0.13.1