When I click on "i'm attending" on this event -

When I click on "i'm attending" on this event - http://65.39.128.43/~aicisydn/events/2014/02/weekend-retreat/ and then click on the Login button with Wordpress. A pop up appears, but it doesn't show the password field, Also when I fill in the other details the pop up doesn't disappear but stays stuck on the page BUT the admin is emailed saying there is a new user.
Please help!
Thank you