Registration issues (Urgent Please)

After Registering on the websitr the users are having the following error:im deleting the login and password for security reasons.

INSERT INTO wp_EWD_FEUP_Users (Username,User_Password,User_Admin_Approved,User_Date_Created,User_Last_Login) VALUES (‘USERLOGINDELETED’,’USERPASSWORDDELETED’,’No’,’2014-09-25 14:14:59′,’2014-09-25 14:14:59′)

Warning: Cannot modify header information – headers already sent by (output started at /home/veneship/public_html/wp-includes/wp-db.php:1253) in /home/veneship/public_html/wp-content/plugins/front-end-only-users/Functions/CreateLoginCookie.php on line 10

i can see new registrations on the recently added backend but when i click on them nothing happens.

this is the registration url http://veneshipping.com/area-de-clientes

this is happening after the last update 2 weeks ago, and i cant find previous versions online to downgrade.

thanks.

https://ww.wp.xz.cn/plugins/front-end-only-users/