When you register on this site, it will send you back an email with a link for you to click on, to confirm your email address. So until you have done this, it won't let you login and will say that your account is "Inactive".
So if you're seeing this message, then have a look in your Spam folders to see if you can find the confirmation message. If you can't, or if you've already clicked on the confirmation link but it's still not letting you in, then please contact us by using the "Contact us" link at the bottom of the board screens, and we'll sort you out.