1. remove a_login.php from your /cache/ folder. That will allow you to try 5 more times. You can continually do it too if you have access to your own ftp.
2.sounds like he has possibly been banned yes. you should seek support from the main dragonfly support site on this one. they will tell you how to unban him. remember, do a forum search first for "bad ip" or something similar. maybe someone ran into the same problem before and has the answer. you might not even have to ask a question if you find the answer.