I think I have found the solution:
$package_role = maybe_unserialize(get_post_meta(get_the_ID(), '__wpdm_access', true));
if(is_array($package_role) && !in_array('guest', $package_role) && !in_array($role, $package_role)) {
continue;
}
in wpdm-archive-page.php was commented. So I added the code and now it seems to be ok.