Thanks for bringing this up. A while a go an anti-spammer question has been added to the required questions list when a new user registered. In the blank field it said "Yaamha Blater" and the only way to continue the registration process was to change that to "Yamaha Blaster". This extra field stops a lot of robot and spam registrations since then.
Members who registered before this field was available, were asked to fill it out in the user cp, but it did not show the 2 word they had to correct causing the current issue. The required value has been filled out for the users who never had to fill that field out and it should no longer be a problem to anyone.