title: Symfony app_dev.php install \DOMDomain error
body: <p>I have installed Symfony on localhost under CentOS under VMware player. (Windows 7, 32 bit)
  My PHP version is 5.3.3.   CentOS is 6.5.  VMware player is 6.0.1.</p>
  
  <p>When I attempt to connect with  <code>localhost/Symfony/web/app_dev.php</code> I get the following error</p>
  
  <blockquote>
    <p>ClassNotFoundException: Attempted to load class "DOMDocument" from the
    global namespace in
    /var/www/html/Symfony/vendor/symfony/symfony/src/Symfony/Component/Config/Util/XmlUtils.php
    line 47.</p>
  </blockquote>
  
  <p>Did you forget a use statement for this class?</p>
  
  <p>line 47 is</p>
  
  <pre><code>$dom = new \DOMDocument();
  </code></pre>
  
  <p>I get 102 hits when I grep "DOMDocument".</p>
  
  <p>Most hits display</p>
  
  <pre><code>$dom = new \DOMDocument();
  </code></pre>
  
  <p>or</p>
  
  <pre><code>$dom = new DOMDocument(); 
  </code></pre>
  
  <p>I had previously installed Symfony on an external server following the same script and was able to exercise <code>app_dev.php</code> without problem. (FreeBSD)</p>
  
  <p>What is the difference between <code>new \DOMDocument();</code>  and <code>new DOMDocument();</code>.
  I am a JavaScript and PHP novice.   Does anyone know what I should do to correct this ? or some clues as to how to trouble-shoot ? </p>