Here are some things you can do to protect against hackerbots and spambots locking out your Admin login accounts & blocking Brute Force Login attacks in general.
Enable / Turn On JTC Anti-Spam / Anti-Hacker: should pretty much eliminate all hackerbot and spambot login attempts/attacks and may be the only thing that you need to do.
Additional info and protection:
http://forum.ait-pro.com/forums/topic/protect-login-page-from-brute-force-login-attacks/
http://forum.ait-pro.com/forums/topic/user-account-locked/
http://forum.ait-pro.com/forums/topic/revealing-the-admin-or-editor-user-name-and-not-knowing/