Hi,
Please edit the file "administrator/components/com_hikashop/classes/product.php" and in the function "backSaveForm()" replace:
if(!hikashop_acl('product/edit/manufacturer')) { unset($product->product_manufacturer_id); }
By:
if(!hikashop_acl('product/edit/manufacturer')) { unset($product->product_manufacturer_id); }else{
if(!is_numeric($product->product_manufacturer_id)){
$this->db->setQuery('SELECT category_id FROM '.hikashop_table('category').' WHERE category_name = '.$this->db->quote($product->product_manufacturer_id));
$result = $this->db->loadResult();
$product->product_manufacturer_id = $result;
}
}