OK, it looks to me like 3.4.x doesn't have the equivalent of that variable, so we'll have to make one. Try adding this somewhere near the top of cart.php.
Code:
if(!$login){
$smarty->assign("not_logged_message","1");
}
else{
$smarty->assign("not_logged_message","0");
}
And, as always, BACK UP!
