This...
$toplinks = '<?php include 'login.php'; ?>';
...needs to be one of these, instead:
$toplinks = '<?php include \'login.php\'; ?>';
// or
$toplinks = '<?php include "login.php"; ?>';
HOWEVER: I highly doubt you really want to do this, as I don't think it will do what you expect it to do. Unless login.php actually returns a value, you'll probably find that $toplinks will always have a value of 1 in this case.