I letterali stringa in SQL sono indicati da virgolette singole ' , non virgolette " , quindi devi sostituire il " come delimitatori di stringa nella tua query di ' :
$query = $em->createQueryBuilder()
->select('u.id, u.username, u.username_canonical, u.email, u.email_canonical, u.last_login, u.name, u.type, u.phone, u.site, u.agency, u.subtype, u.info, u.created_date,u.vip')
->from('ContrateAdminBundle:Fosuser', 'u')
->where('u.created_date BETWEEN \'${fromdateaccounts}\' AND \'{$todateaccounts}\'')
->getQuery();