title: Magento: Fatal error: Call to a member function getModelInstance() on a non-object in app\Mage.php on line 432
body: <p>I want to call a PHP file using ajax where in that PHP i will place order by the ajax call. But it throws error while i am using app/Mage.php from that file</p>
  
  <pre><code>require_once '../../../../../../../../../../app/Mage.php';    
  $customer = Mage::getModel('customer/customer');
  </code></pre>
  
  <p>then it says </p>
  
  <blockquote>
    <p>Fatal error: Call to a member function getModelInstance() on a
    non-object in app\Mage.php on line 432</p>
  </blockquote>
  
  <p>Can anyone please help me???</p>