white page on wp-login.php

Hi,
I installed and configured the plugin all things seems fine but after i restrict specified pages it displayed login box and when i try to login it leads me to white page on wp-login.php. On wp debug on i found the following errors

Notice: Undefined variable: user_login in /htdocs/wp-content/plugins/pagerestrict/pagerestrict.php on line 60 Notice: wp_specialchars is deprecated since version 2.8! Use esc_html() instead. in /htdocs/wp-includes/functions.php on line 3201

Looking to hear from you.
Regards,

https://wordpress.org/plugins/pagerestrict/