M42Club is plagued with spammers, and the reason is probably because of a software package called XRumer. It allows a user to spam thousands of forums/subforums with little effort. It can defeat captcha registration that is sometimes used to register new forum users. IP banning isn't very effective because the software uses a database of proxies. 
I suggest that M42club modify the user registration form as described in this Wikipedia article: 
http://en.wikipedia.org/wiki/XRumerOver on S14.net we've been getting some of the same type of forum spamming and I suggested that the admins try to contact the software author and get their site blacklisted (that is, removed from the spam database).  Towards the end of this interview with the author, he indicates that such a thing is possible:  
http://xrumer-palladium.blogspot.com/2009/03/interview-with-xrumer-author.htmlUnfortunately the Xrumer site has no contact info, but I think this site could honor a blacklist request, or put you in contact with the XRumer author:
http://www.botmasternet.com/contacts/Cheers,
Colin