Ok, so there is no *logical* reason why this user is getting that message then. Like I said, the only time that appears is when the U_Banned field returns a 1.
Perhaps this user is trying to login with the wrong username maybe? I'm pretty sure in classic usernames were case sensitive and in threads they are not. Perhaps someone else had the same username, different case and was banned. I'm kinda grasping at straws here because like I said, there's no logical reason for that to be happening.
Can you find out what exactly name she is logging in with and then run this query:
select U_Banned from w3t_Users where U_LoginName='herloginname'
