When adding a new computer from the client, and the computer already exist, the client seems to be stuck in a loop saying:
...... This computer already exists
** Enter a computer name to register **
I could see that happening. If it's just the name that already exists, you can try a new name that's why the loop is there. But if it's the mac address that already exists, then yes you'll be in an infinite loop. I can look into this, but don't think it's a big issue since you typically don't try to add computers that have already been added.