Redmine

I recently upgraded my Redmine project management system from version 2.0 to 2.3

While all features appear to work good, I am unable to get onto the My account & Settings.

Here is the error message that I get when I click the My account link,

[ 2013-04-25 21:55:31.9684 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr] 
[ 2013-04-25 21:55:31.9684 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr] ActionView::Template::Error (Permission denied - /opt/redmine-2.3/tmp/cache/900):
[ 2013-04-25 21:55:31.9685 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     16:   <p><%= f.text_field :firstname, :required => true %></p>
[ 2013-04-25 21:55:31.9685 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     17:   <p><%= f.text_field :lastname, :required => true %></p>
[ 2013-04-25 21:55:31.9685 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     18:   <p><%= f.text_field :mail, :required => true %></p>
[ 2013-04-25 21:55:31.9685 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     19:   <p><%= f.select :language, lang_options_for_select %></p>
[ 2013-04-25 21:55:31.9685 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     20:   <% if Setting.openid? %>
[ 2013-04-25 21:55:31.9685 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     21:   <p><%= f.text_field :identity_url  %></p>
[ 2013-04-25 21:55:31.9686 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     22:   <% end %>
[ 2013-04-25 21:55:31.9686 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   lib/redmine/i18n.rb:95:in `languages_options'
[ 2013-04-25 21:55:31.9686 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/helpers/application_helper.rb:929:in `lang_options_for_select'
[ 2013-04-25 21:55:31.9686 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/views/my/account.html.erb:19:in `block in _app_views_my_account_html_erb___1141987887325908415_69999284087820'
[ 2013-04-25 21:55:31.9686 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/helpers/application_helper.rb:944:in `labelled_form_for'
[ 2013-04-25 21:55:31.9686 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/views/my/account.html.erb:9:in `_app_views_my_account_html_erb___1141987887325908415_69999284087820'
[ 2013-04-25 21:55:31.9687 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr] 
[ 2013-04-25 21:55:31.9687 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]

Here is the error that I get when I click on Settings under Administration.

[ 2013-04-25 21:56:51.7664 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr] 
[ 2013-04-25 21:56:51.7665 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr] ActionView::Template::Error (Permission denied - /opt/redmine-2.3/tmp/cache/900):
[ 2013-04-25 21:56:51.7665 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     3: <div class="box tabular settings">
[ 2013-04-25 21:56:51.7666 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     4: <p><%= setting_select :ui_theme, Redmine::Themes.themes.collect {|t| [t.name, t.id]}, :blank => :label_default, :label => :label_theme %></p>
[ 2013-04-25 21:56:51.7666 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     5: 
[ 2013-04-25 21:56:51.7666 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     6: <p><%= setting_select :default_language, lang_options_for_select(false) %></p>
[ 2013-04-25 21:56:51.7667 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     7: 
[ 2013-04-25 21:56:51.7667 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     8: <p><%= setting_select :start_of_week, [[day_name(1),'1'], [day_name(6),'6'], [day_name(7),'7']], :blank => :label_language_based %></p>
[ 2013-04-25 21:56:51.7667 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]     9: <% locale = User.current.language.blank? ? ::I18n.locale : User.current.language %>
[ 2013-04-25 21:56:51.7668 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   lib/redmine/i18n.rb:95:in `languages_options'
[ 2013-04-25 21:56:51.7668 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/helpers/application_helper.rb:929:in `lang_options_for_select'
[ 2013-04-25 21:56:51.7669 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/views/settings/_display.html.erb:6:in `block in _app_views_settings__display_html_erb___3366814545991254811_59076160'
[ 2013-04-25 21:56:51.7669 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/views/settings/_display.html.erb:1:in `_app_views_settings__display_html_erb___3366814545991254811_59076160'
[ 2013-04-25 21:56:51.7670 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/views/common/_tabs.html.erb:24:in `block in _app_views_common__tabs_html_erb___3692719548756668757_57720620'
[ 2013-04-25 21:56:51.7670 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/views/common/_tabs.html.erb:23:in `each'
[ 2013-04-25 21:56:51.7670 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/views/common/_tabs.html.erb:23:in `_app_views_common__tabs_html_erb___3692719548756668757_57720620'
[ 2013-04-25 21:56:51.7671 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/helpers/application_helper.rb:271:in `render_tabs'
[ 2013-04-25 21:56:51.7671 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/views/settings/edit.html.erb:3:in `_app_views_settings_edit_html_erb__4272321134920229542_57630980'
[ 2013-04-25 21:56:51.7671 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]   app/controllers/settings_controller.rb:28:in `index'
[ 2013-04-25 21:56:51.7672 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr] 
[ 2013-04-25 21:56:51.7672 690/7f36044d2700 Pool2/Implementation.cpp:1137 ]: [App 28208 stderr]