submit form on popup

Hello,
I have contact form on popup with captcha but then when I click submit button it brings me to the top of the form – here you can check: http://ledlive.pl/nasz-zespol/
when you click “click here” button – there is no captcha and it works ok but when click this button (on screen: http://screencast.com/t/bumeSCDw5YQ ) it has captcha and after submit it brings to the top of the top without sending. Only the second attempt to send is successful

Could you help me with this?

Regards

https://ww.wp.xz.cn/plugins/really-simple-captcha/