From the guidance in that link, try changing this in login.php:
if($xpw) $adminpw='';
setcookie('LMadm1',md5($instid),0,'/','.'.getdomain(),0);
setcookie('LMadm2',md5($adminpw),0,'/','.'.getdomain(),0);
To
if($xpw) $adminpw='';
setcookie('LMadm1',md5($instid));
setcookie('LMadm2',md5($adminpw));
That could allow you to login, but you may not be able to logout. You would need to search for "setcookie" and trim each call down to 2 paramaters as we have done with the login cookies.
Regards