That link takes me to a guide on how to use basic prestashop's translations... Vertical mega menu does not takes translations from there, it stores the translations in the database not in php files. The ítems and contents of this module are stored and taked from the database, the module as I told you since last week is storing correctly the translations in the database but it's not building correctly its output. So the problem is directly there, it does not have anything to do with the translations page... Do you have a fix or not?