title: magento backend unable to login Fatal error getBlockName
body: <p>Running on Magento 1.8</p>
  
  <p>I was copying to a test production site but at the backend I couldn't login and this is the error message. </p>
  
  <pre><code>Fatal error: Call to a member function getBlockName() on a non-object in /var/www/test/app/code/core/Mage/Captcha/Block/Captcha.php on line 43
  </code></pre>
  
  <p>To solve this problem usually we delete <code>var/cache</code> folder, but the problem is on this test site we don't have a <code>var</code> folder so I'm not sure what is causing the error.</p>
  
  <p>Here is the <a href="https://www.nubex.my/test/index.php/admin" rel="nofollow">link</a></p>