Error on search product from admin panel

[kingstyle]

i get this error message when i type a product name...

vmError: exeSortSearchListQuery Unknown column 'product_gtin' in 'where clause' SQL=SELECT SQL_CALC_FOUND_ROWS p.`virtuemart_product_id` FROM `xi8k1_virtuemart_products` as p LEFT JOIN `xi8k1_virtuemart_products_el_gr` as l using (`virtuemart_product_id`) LEFT JOIN `xi8k1_virtuemart_product_manufacturers` ON p.`virtuemart_product_id` = `xi8k1_virtuemart_product_manufacturers`.`virtuemart_product_id` WHERE ((`product_name` LIKE "%testProduct%" OR `product_sku` LIKE "%testProduct%" OR `product_gtin` LIKE "%testProduct%" OR `product_mpn` LIKE "%testProduct%" OR `l`.`slug` LIKE "%testProduct%" OR `product_s_desc` LIKE "%testProduct%" OR `l`.`metadesc` LIKE "%testProduct%") AND `xi8k1_virtuemart_product_manufacturers`.`virtuemart_manufacturer_id` = 11) group by p.`virtuemart_product_id` ORDER BY p.`created_on` DESC LIMIT 0, 20