title: Error 500 when including/requiring src/facebook.php from Facebook PHP SDK
body: <p>I'm working to implement a Facebook login for my website. I have limited knowledge of php debugging so I'm more or less looking for a good approach to debug this.</p>
  
  <p>As soon as I include (or require) the <code>facebook.php</code> file, with no other SDK interaction, Apache will 500 my PHP script.</p>
  
  <pre><code>include('fb-php-sdk/src/facebook.php');
  </code></pre>
  
  <p><code>fb-php-sdk</code> is a directory within the directory that contains our PHP script (also the document root)</p>
  
  <hr>
  
  <p>Server log:</p>
  
  <pre><code>[Tue Nov 15 23:18:16 2011] [error] [client 192.168.1.110] PHP Fatal error: Uncaught exception 'Exception' with message 'Facebook needs the CURL PHP extension.'
  
  in /var/www/fb-php-sdk/src/base_facebook.php:19\nStack trace:
  
  #0 /var/www/fb-php-sdk/src/facebook.php(18): require_once()
  #1 /var/www/index.php(13): include('/var/www/fb-php...')
  #2 {main} thrown in /var/www/fb-php-sdk/src/base_facebook.php on line 19 
  
  From /var/log/apache2/error.log 
  </code></pre>