CMS Made Simple Forums

Hi!
Is there anybody with a solution for the following:
When a user wants to validate the filled registration form they receive the following error in the browser, when they click on the link (send by email, that works!)

Fout! Of het formulier heeft geen form_builder dispositie, of het is mislukt te instantieren (als gevolg van geheugenproblemen?).
Fatal error: Call to a member function GetOption() on a non-object in /home/XXX/domains/XXX.nl/public_html/modules/FormBuilder/FormBuilder.module.php on line 428

Thnx!

What version of CMS-MS and what version of FormBuilder?

My CMS version is 1.9.4.1;
And the FormBuilder is 0.6.4.

I hope you can give an explanation!
Thnx..

Anyone, who can give a solution?
Maybe I have to save the filled in forms first with FormBrowser? or isn't it necessary to use form browser with validation...