For security reasons these forums are set to use verification until new users have made 5 posts. This encourages genuine participation from valid members that are interested.
Against IT community advice, the secret questions have been disabled to keep security as pain free as possible.
Here's a quote, in English, from an expert developer and tester of this type of website:
"Spammers have been targetting phpBB/SMF quite a bit recently. One thing you can do is to install reCAPTCHA ...it's regarded as the best CAPTCHA out there.
Also, anti-bot puzzles are invaluable - these are standard in SMF 2.0, and although it's only in RC I'd fully recommend the 2.0 branch. If not, look for an anti-bot puzzle/question mod for the 1.1 branch.
Bots have got very clever recently, and can break reCAPTCHA sometimes, although nothing can really break through anti-bot puzzles/questions (I ask things like: "What is 2 + 5 - 1, answer in words?" and things like that etc)"
Please be patient with the security features that I've implemented. They are for the protection of our site and our community. If you post five times, they'll go away.