Redmine

I am trying to update from 2.1 to 2.2 because I really need the REST impersonation feature. But after updating following the wiki steps I am having the following error, when trying to access "settings". Is it a bug, or did I miss something?

ActionView::Template::Error (Permission denied - /usr/share/redmine/tmp/cache/900):
3: <div class="box tabular settings">
4: <p><%= setting_select :ui_theme, Redmine::Themes.themes.collect {|t| [t.name, t.id]}, :blank => :label_default, :label => :label_theme ></p>
5:
6: <p><= setting_select :default_language, lang_options_for_select(false) ></p>
7:
8: <p><= setting_select :start_of_week, day_name(1),'1'], [day_name(6),'6'], [day_name(7),'7', :blank => :label_language_based ></p>
9: < locale = User.current.language.blank? ? ::I18n.locale : User.current.language %>
lib/redmine/i18n.rb:95:in `languages_options'
app/helpers/application_helper.rb:975:in `lang_options_for_select'
app/views/settings/_display.html.erb:6:in `block in app_views_settings_display_html_erb___3357048038777046272_57623500'
app/views/settings/_display.html.erb:1:in `_app_views_settings__display_html_erb___3357048038777046272_57623500'
app/views/common/_tabs.html.erb:24:in `block in app_views_common_tabs_html_erb__822520276650112120_56564720'
app/views/common/_tabs.html.erb:23:in `each'
app/views/common/_tabs.html.erb:23:in `_app_views_common__tabs_html_erb__822520276650112120_56564720'
app/helpers/application_helper.rb:263:in `render_tabs'
app/views/settings/edit.html.erb:3:in `_app_views_settings_edit_html_erb___560253790034141303_42312580'
app/controllers/settings_controller.rb:26:in `index'