title: magento web service filter product list error Call to a member function getBackend() on a non-object
body: <p>I'm using visual studio 2010 service reference to consume magento soap v2 api web service.</p>
  
  <p>php 5.3.8, magento 1.6 install on windows 7 iis 7.5</p>
  
  <p>I can log in and list all the product, but as soon as i put a filter there is an exception</p>
  
  <p>Call to a member function getBackend() on a non-object</p>
  
  <p>php error log:</p>
  
  <p>PHP Fatal error:  Call to a member function getBackend() on a non-object in C:\inetpub\wwwroot\Magento1620\app\code\core\Mage\Eav\Model\Entity\Abstract.php on line 816</p>
  
  <pre><code>static void TestMagentoSoapV2Wcf()
      {
          MagentoService magentoService = new MagentoService();
  
          MageSvcRef.associativeEntity assoEntity = new MageSvcRef.associativeEntity();
          assoEntity.key = "like";
          assoEntity.value = "n2610";
  
          MageSvcRef.complexFilter complexFilter = new MageSvcRef.complexFilter();
          complexFilter.key = "sku";
          complexFilter.value = assoEntity;
  
          MageSvcRef.complexFilter[] compFilters = new MageSvcRef.complexFilter[1];
          compFilters[0] = complexFilter;
  
          MageSvcRef.filters filters = new MageSvcRef.filters();
          filters.complex_filter = compFilters;
  
          string sessionId = magentoService.login("zzc000", "zzc000");
  
          var products = magentoService.catalogProductList(sessionId, filters, string.Empty);
      }
  </code></pre>
  
  <p>Please help</p>
  
  <p>Thanks</p>