Usa esto
$Query72 ="insert into product (product_id,model,sku,upc,location,quantity,stock_status_id,image, manufacturer_id, shipping, shippingamount, price, points, tax_class_id, date_available, weight, weight_class_id, length, width, height, length_class_id, subtract, minimum, sort_order, status, date_added, date_modified,viewed)
values('', '".$model."', '".$sku."', '".$upc."', '".$location."', '".$quantity."','".$stock_status_id."', '".$image."', '".$manufacturer_id."', '".$shipping."', '".$shippingamount."', '".$price."', '".$points."', '".$tax_class_id."', '".$date_available."', '".$weight."', '".$weight_class_id."', '".$length."', '".$width."', '".$height."','".$length_class_id."','".$subtract."','".$minimum."','".$sort_order."', '".$status."','".$date_added."','".$date_modified."','".$viewed."')";
Que te ayude.
Este error ocurrió porque no estás usando las comillas correctamente. En su consulta, el valor de la fecha debe estar entre comillas simples.
