title: Capybara Selenium click_link: undefined method `start_with?' for nil:NilClass
body: <p>I'm using Capybara 2.1.0 and Selenium-Webkit 2.38.0 gems to test a Rails 3.2.13 app.</p>
  
  <p>I have the following test:</p>
  
  <pre><code>visit my_favorite_path
  click_link_or_button 'Share'
  page.should have_link 'Send Email'
  click_link_or_button 'Send Email'
  last_email.should be_present
  </code></pre>
  
  <p>Which is failing on the second "click_link_or_button" with the following (very opaque) error:</p>
  
  <pre><code>Failure/Error: click_link_or_button 'Send Email'
  NoMethodError:
     undefined method `start_with?' for nil:NilClass
  </code></pre>
  
  <p>I get the same error when I replace the offending line with <code>click_link 'Send Email'</code> or <code>first(:link, 'Send Email').click</code>.</p>
  
  <p>What could be the problem here? The third line of the test passes, seemingly confirming that the link exists, but then trying to click the link fails with this very unhelpful error.</p>