rosa-build/lib/ext/rails/render_errors_in_forms.rb

ActionView::Base.field_error_proc = Proc.new do |html_tag, instance|
  if html_tag =~ /<label/
    %|<div class="fieldWithErrors">#{html_tag} <span class="error">#{[instance.error_message].join(', ')}</span></div>|.html_safe
  else
    html_tag
  end
end