[Typo3] Problems with tip-a-friend/captcha

[Wolf-Nicolas Henkels]

Hi.

I've just installed the Tip-A-Friend-Update with the new Extension 
Captcha on my Typo3 3.7.0. Since this Update my Form doesn't work 
anymore and when I use the original template from the extension the 
marker ###CAPTCHA_HTML### will not be replaced on my website. Is this a 
bug or what else i have to do to get things running again?

Thanks for any hint,
Nico