After too many failed login attempts you've been locked out of the admin area or normal front-end login.
This can be cleared by executing the below SQL on your database. You can do this via phpMyAdmin or similar. Replace the '1.2.3.4' with your own public IP (found here: http://www.whatsmyip.org/).DELETE FROM `banned_ips` WHERE ipAddress = '1.2.3.4';DELETE FROM `login_failure` WHERE ip_address = '1.2.3.4';
Note:
You can raise the number of allowed failures via the script admin area, site settings. Within the "security" section find "Security Block Ip Login Attempts" and increase this as needed.