Fatal error on only some of my category pages

Question

I updated yesterday to 1.9 CE and now my category pages I get this fatal error:

Fatal error: Call to undefined method Mage_Catalog_Model_Resource_Category_Flat_Collection::joinUrlRewrite() in /home/senorehe/public_html/app/code/local/Mage/Catalog/Block/Navigation.php on line 155

This is the section it is referring to

public function getCurrentChildCategories()
   {
        $layer = Mage::getSingleton('catalog/layer');
        $category   = $layer->getCurrentCategory();
        /* @var $category Mage_Catalog_Model_Category */
        $collection = Mage::getModel('catalog/category')->getCollection();
        /* @var $collection Mage_Catalog_Model_Resource_Eav_Mysql4_Category_Collection */
        $collection->addAttributeToSelect('url_key')
            ->addAttributeToSelect('name')
            ->addAttributeToSelect('is_anchor')
            ->addAttributeToSelect('image') 
            ->addAttributeToFilter('is_active', 1)
            ->addIdFilter($category->getChildren())
            ->setOrder('position', 'ASC')
line 155        ->joinUrlRewrite()
            ->load();

        $productCollection = Mage::getResourceModel('catalog/product_collection');
        $layer->prepareProductCollection($productCollection);
        $productCollection->addCountToCategories($collection);
        return $collection;
    } 

I have tried reindexing the URL, flushing my mage_core_url_rewrite then reindexing. But nothing had worked so far.

Can anybody help me with this?