title: A model's collection turns out to be a non-object
body: <p>I am trying to get a list of viewed products in Magento, but the following code:</p>
  
  <pre><code>$model = Mage::getModel('reports/product_index_viewed')-&gt;getCollection()
      -&gt;addAttributeToFilter('store_id', array('eq' =&gt; 1));
  </code></pre>
  
  <p>created the error message:</p>
  
  <p>Fatal error: Call to a member function getBackend() on a non-object in C:\xampp\htdocs\magento\app\code\core\Mage\Eav\Model\Entity\Abstract.php on line 816</p>
  
  <p>Why is the collection returned in getCollection() a non-object?</p>