Something to consider when internationalizing your app in Rails, watch for spacing and how you form your arguments. I ran into a problem where my "I18n.t" tags were working on my development machine but then when porting to a different box, it completely crapped out. The culprit:

<%= link_to I18n.t 'finish.tag_begin',
"http://www.facebook.com/photo.php?pid=#{@photo_id}&id=#{@current_user.facebook_id}"
%> <%= I18n.t 'finish.tag_end' %>

Notice where "link_to" and "I18n.t" are in close proximity. It seems that my MacOS was more forgiving with the aforementioned syntax. Instead, make sure to put parentheses whenever you find yourself working with helper tags/methods that are in close proximity:

 <%= link_to I18n.t('finish.tag_begin'),
"http://www.facebook.com/photo.php?pid=#{@photo_id}&id=#{@current_user.facebook_id}"
%> <%= I18n.t 'finish.tag_end' %>