CF5 - captcha error message shows every time on load

I made a form in CF4 with captcha and transformed it to CF5.
Everything works fine, but the message "you typed the wrong code" shows up every time the form is loaded. It works fine then, but first it irritates the user.
Here is the link:

http://www.bdg-online.org/index.php/startseite/anmeldung-zum-bdg-kongress

(i have the last joomla update and converselite template...)

HI christallo,

Do you have a Check Captcha action in the form On Load event? If so please try removing it.

Bob

Thanks - that was it!!!