CMS Made Simple Forums

I wanted to use Securimage CAPTCHA in my own guestbook page, however, it needs to use session_start() in a CMSMS-page, and that doesn't seem to work. My page works on it's own (without CMSMS) fine. Is there a way around this?

I would suggest you to use some stand-alone CAPTCHA script, because CMSMS one is designed for CMSMS itself and might be time consuming to figure out how to run it stand-alone.