That is for security reasons in almost all forums around the globe and all vBulletin boards. I am sure its here as well.
Thank you that worked. I had to pick a different email address (googlemail instead of gmail) because otherwise I just got a message saying that the email account is already associated with an account and no verification email was sent.
It gave the error because probably the gmail account is already registered here by this or any other username for some reason.
Glad you got it sorted out.