add check that will wait for elements to load before asserting presence

features/step_definitions/generic_steps.rb

@@ -17,6 +17,8 @@ end
 
 Then /^I should see an error flash message saying "([^"]*)"$/ do |message|
   xpath = "//div[@id='message_holder']/h4[@id='flash']"
+  page.should have_xpath(xpath, :visible => true)
+  
   text = page.find(:xpath, xpath).text
   text.should == message
 end