diff --git a/src/app/code/community/IntegerNet/Solr/Model/Observer.php b/src/app/code/community/IntegerNet/Solr/Model/Observer.php
index 79654ea..58edaf0 100644
--- a/src/app/code/community/IntegerNet/Solr/Model/Observer.php
+++ b/src/app/code/community/IntegerNet/Solr/Model/Observer.php
@@ -340,7 +340,7 @@ public function afterFlatCategoryLoadedUseBackendModel(Varien_Event_Observer $ob
             return;
         }
 
-        if (Mage::helper('catalog/category_flat')->isEnabled() && !$category->getResource() instanceof Mage_Catalog_Model_Resource_Category_Flat) {
+        if (!Mage::helper('catalog/category_flat')->isEnabled() || !$category->getResource() instanceof Mage_Catalog_Model_Resource_Category_Flat) {
             return;
         }