Product Version: NetBeans IDE Dev (Build 200711161200)
Java: 1.6.0_03; Java HotSpot(TM) Client VM 1.6.0_03-b05
System: Windows XP version 5.1 running on x86; MS932; ja_JP (nb)

I'm not sure if this is the same as bug 121229, but here is the code. 
A Ja community member is complaining that error should not happen.

---
<% form_for :document, @document,
  :url => { :action => 'update', :id => @document } do %>
<% if @revision %><%= hidden_field_tag :revision, @revision %><% end %>
<%= submit_tag 'Save' %>
<% end %>
---

There will be no error when I changed to the following,
--
<% form_for :document, @document,
  :url => { :action => 'update', :id => @document } do %>
<% if @revision %>
<%= hidden_field_tag :revision, @revision %>
<% end %>
<%= submit_tag 'Save' %>
<% end %>
--

When I entered Return just after "<% if @revision %>",
unexpected "end" was inserted, like

--
<% form_for :document, @document,
  :url => { :action => 'update', :id => @document } do %>
<% if @revision %>
  <%= hidden_field_tag :revision, @revision %><% end %>
end
<%= submit_tag 'Save' %>
<% end %>
--