Where are date_select_tag ?

Hi! I want a date_select_tag inside a form_tag

But it does not work!

I looked for the docs at: rails.info

And even, if I copy the code right inside - there are an error!

ActionView::Template::Error (can't convert Symbol into String) on line #30 of /Users/kb1/code/rails/rateurdate/app/views/miniprofile/ meantimes/show_birthdate.fbml.erb: 27: <h1>t('miniprofile.meantimes.show_birthdate.headline'<br /

<span style="color:#98b8ce;"><%=

t('miniprofile.meantimes.show_postcode.subtitle') %></span></h1> 28: <% form_tag meantime_miniprofile_url(:type => :birthdate), :method => :post do |f| %> 29: <br><br><br> 30: <%= date_select("post", "written_on") %> 31: <br><br><br> 32: <br class="clear" /> 33: <br>

    app/views/miniprofile/meantimes/show_birthdate.fbml.erb:30:in `block in _render_template__2824634172748094325_2184188140_3813724702546118430'     app/views/miniprofile/meantimes/show_birthdate.fbml.erb:28:in `_render_template__2824634172748094325_2184188140_3813724702546118430'     app/controllers/miniprofile/meantimes_controller.rb:10:in `show'

This is the whole code:     <% form_tag meantime_miniprofile_url(:type => :birthdate), :method => :post do |f| %>     <br><br><br>     <%= date_select("post", "written_on") %>     <br><br><br>     <br class="clear" />     <br>     <div class="buttons">       <%= image_submit_tag "btn-weiter.png" %>     </div>

    <% end -%>