Every now and then some (pardon the language) arsehole spambots decide to hit a forum simply to get their web address known to the search engines... These spambots are automated scripts who's sole intention is to fill the web with their porn, online gambling, or drugs websites...
Recently Paddleducks has been plagued by these automated scripts who are currently using yahoo.com as their email address to regsiter an account. So for now ALL yahoo.com email addresses have been blocked and no-one will be able to register using them.
I realise this will cause problems for a few genuine users, and I apologise for that, but for now I can only suggest you use a hotmail or similar email address to register - It MUST be a valid address as you have to respond to an email in order to activate your account!
This block on yahoo.com will be removed in a few weeks - At which time I hope the scripts will have given up and gone elsewhere for a while - Some hope! :-)