end_form_tag

Remove the = it isn't supposed to write out end, only close the loop,
thus you want

<% end %> instead of <%= end %>

<% form_remote_tag :url =>{:action => "next_question"} do %>
# Form contents...
<% end %>

Form tag helpers should not use <%= %> if you're trying to pass them a
block. They should use <% %>.

Alternatively, you could use:

<%= form_remote_tag :url =>{:action => "next_question"} %>
# Form contents...
</form>

But that's not as pretty. See DHH's article on the topic:
http://www.loudthinking.com/arc/2006_10.html

See also the following for examples of the syntax:
http://api.rubyonrails.org/classes/ActionView/Helpers/FormTagHelper.html#M000601

Hope this helps.

-PJ