ADG - signup page - form validation appears over captcha (BB-11700)

!3636324677-Screen%20Shot%202014-12-12%20at%2010.22.34%20am.png|thumbnail!1. Go to bitbucket signup page. Ensure you're a new user so you'll get a captcha
2. enter a username that already exists
3. Press submit

The validation message appears over captcha form (see attached screenshot)