Submit open the site in a new tab and dont submit.

Hi guys

i have a problem with the captcha plugin. allways when i hit submit the site open up in a new tab but it dont submit it. what am i doing wrong?

The code for the Form:

<p>Name / Nachname<br>[text* your-name] </p>

<p>E-Mail Adresse<br>[email* your-email] </p>

<p>Geburtsdatum<br>[text* your-subject] </p>
<p>[captchac captcha-170] [captchar captcha-170 4/4]</p>
<p>[submit "Senden"]</p>

The Original Site load over facebook. The error exist also in the wordpress page.
http://goo.gl/jQCTV

http://wordpress.org/extend/plugins/really-simple-captcha/