This should fix it:
In login.php do a search for "setcookie". The following modifications should be made in each (2 line) result:
setcookie ('LMadm1','',time()-2592000);
setcookie ('LMadm2','',time()-2592000);
setcookie ('LMadm1','',time()-2592000);
setcookie ('LMadm2','',time()-2592000);
setcookie('LMadm1',md5($instid));
setcookie('LMadm2',md5($adminpw));
Please let me know if you continue to have troubles.
This fix will be included in all future updates.
Regards, DW