Redmine

When I try to create a new custom field (Administration-->custom fields-->new custom field-->next) I get a internal server error
redmine.log

I, [2016-02-16T14:36:36.937184 #4482]  INFO -- : Processing by CustomFieldsController#new as HTML
I, [2016-02-16T14:36:36.937424 #4482]  INFO -- :   Parameters: {"utf8"=>"✓", "type"=>"UserCustomField"}
I, [2016-02-16T14:36:36.950620 #4482]  INFO -- :   Current user: **** (id=77)
I, [2016-02-16T14:36:36.999510 #4482]  INFO -- :   Rendered custom_fields/formats/_regexp.html.erb (1.3ms)
I, [2016-02-16T14:36:37.002628 #4482]  INFO -- :   Rendered custom_fields/formats/_string.html.erb (4.7ms)
I, [2016-02-16T14:36:37.003024 #4482]  INFO -- :   Rendered custom_fields/_form.html.erb (9.1ms)
I, [2016-02-16T14:36:37.003292 #4482]  INFO -- :   Rendered custom_fields/new.html.erb within layouts/admin (12.2ms)
I, [2016-02-16T14:36:37.003850 #4482]  INFO -- : Completed 500 Internal Server Error in 66ms (ActiveRecord: 1.7ms)
F, [2016-02-16T14:36:37.008606 #4482] FATAL -- : 
ActionView::Template::Error (undefined method `accessor' for #<ActiveRecord::Type::Value:0x007f4841b00f50>):
    1: <%= render :partial => 'custom_fields/formats/regexp', :locals => {:f => f, :custom_field => custom_field} %>
    2: <p><%= f.check_box :text_formatting, {:label => :setting_text_formatting, :data => {:disables => '#custom_field_url_pattern'}}, 'full', '' %></p>
    3: <p><%= f.text_field(:default_value) %></p>
    4: <p><%= f.text_field :url_pattern, :size => 50, :label => :label_link_values_to %></p>
  lib/redmine/views/labelled_form_builder.rb:34:in `check_box'
  app/views/custom_fields/formats/_string.html.erb:2:in `_app_views_custom_fields_formats__string_html_erb___865231022302629170_69974157773900'
  app/helpers/custom_fields_helper.rb:57:in `render_custom_field_format_partial'
  app/views/custom_fields/_form.html.erb:18:in `_app_views_custom_fields__form_html_erb__464940759835363021_69974157611020'
  app/views/custom_fields/new.html.erb:6:in `block in _app_views_custom_fields_new_html_erb__3098139756292135535_69974157542200'
  app/helpers/application_helper.rb:1027:in `labelled_form_for'
  app/views/custom_fields/new.html.erb:5:in `_app_views_custom_fields_new_html_erb__3098139756292135535_69974157542200'
  lib/redmine/sudo_mode.rb:63:in `sudo_mode'

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Environment:
  Redmine version                3.1.1.stable
  Ruby version                   2.1.5-p273 (2014-11-13) [x86_64-linux]
  Rails version                  4.2.4
  Environment                    production
  Database adapter               Mysql2
SCM:
  Subversion                     1.8.8
  Git                            1.9.1
  Filesystem                     
Redmine plugins:
  redmine_my_page                0.1.7