Magento product page not found / magento product page 404 error

http://stackoverflow.com/questions/17809796/magento-404-error-in-public-product-page

If table report_event_types is empty

Go to your DB and run this SQL query:

INSERT INTO `report_event_types` (`event_type_id`, `event_name`, `customer_login`) 

VALUES
(1, 'catalog_product_view', 1),
(2, 'sendfriend_product', 1),
(3, 'catalog_product_compare_add_product', 1),
(4, 'checkout_cart_add_product', 1),
(5, 'wishlist_add_product', 1),
(6, 'wishlist_share', 1);

P.S. check DB name prefix if you have it!

Another way

Go to Mage\Catalog\controllers\ProductController.php and change viewAction() actions code:
from (line 140)

} else {
     Mage::logException($e);
     $this->_forward('noRoute');
}

to

} else {
    echo "<pre>";
    var_dump($e);
    Mage::logException($e);
    //$this->_forward('noRoute');
}