Fatal error: Call to a member function getId() on a non-object in
The line that is giving error is the last line in the below code:

<?php
    $_productCollection=$this->getLoadedProductCollection();
    $_productCollection->addAttributeToSelect('news_from_date')
        ->addAttributeToSelect('news_to_date');
    $_helper = $this->helper('catalog/output');
    $store = Mage::app()->getStore();
    $code  = $store->getCode();
?>
<?php $_helper = $this->helper('catalog/output');?>
<?php $_category_detail=Mage::registry('current_category');?>
<?php
    $products_count = Mage::getModel('catalog/category')->load($_category_detail->getId())->getProductCount();
?>