Redmine

I do the following things.
go to project settings wiki , click delete button.

and then , the project wiki tab disappear.

and I can not go to this project settings.

I still can see other project's wiki and settings.

Completed 500 Internal Server Error in 70ms

ActionView::Template::Error (First argument in form cannot contain nil or be emp ty):
1: <%= labelled_form_for wiki wiki,
2: :as => :wiki,
3: :url => { :controller => 'wikis', :action => 'edit', : id => Herve Harster },
4: :remote => true, :method => 'post' do |f| %>
app/helpers/application_helper.rb:1047:in `labelled_form_for'
app/views/projects/settings/_wiki.html.erb:1:in `_app_views_projects_settings_ wiki_html_erb_2849060791824469656_70013448407720'
app/views/common/_tabs.html.erb:22:in `block in app_views_common_tabs_html_e rb___1457674944382063957_70013446561960'
app/views/common/_tabs.html.erb:21:in `each'
app/views/common/_tabs.html.erb:21:in `_app_views_common__tabs_html_erb___1457 674944382063957_70013446561960'
app/helpers/application_helper.rb:324:in `render_tabs'
app/views/projects/settings.html.erb:3:in `_app_views_projects_settings_html_e rb___493241672892030800_70013446548560'