title: PHP "Class not found" error when extending class Exception
body: <p>I'm getting a page with the following message:</p>
  
  <blockquote>
    <p>Fatal error: Class 'Exception' not found in /home/mysite/public_html/lib/Varien/Exception.php on line 29</p>
  </blockquote>
  
  <p>Here is the line that generates the error:</p>
  
  <pre><code>class Varien_Exception extends Exception {} 
  </code></pre>
  
  <p>Changing the line to call the global namespace (\Exception) doesn't help, I'm still getting the same message. Additionally, I don't get an autoloader warning about a missing file for the exception class, as I would get for using <code>extends Exception22 {}</code> for example.</p>
  
  <p>The error started to show up after migration of a magento 1.3 CE installaion to a new server. I get it whenever I'm trying to open Magento Connect manager.
  The error page url looks like this: <a href="http://[MYSITE.COM]/index.php/admin/extensions_local/index/key/[SOMEID]/" rel="nofollow">http://[MYSITE.COM]/index.php/admin/extensions_local/index/key/[SOMEID]/</a></p>
  
  <p>I'm using PHP 5.4.39, and I can extend and use Exception in other PHP files.</p>