when you select a user for deletion, they arent actually deleted right then. they are queued for deletion and then deleted when the command is processed. in bes 4.1 you can see users in pending delete state and manually purge them but im not sure where to do this in bes 5.0 yet.
this sounds like what is happening to you since it says the users already exists.
Two months ago, I saw a provocative movie on cable TV. It was called The Net, with that girl from the bus.