It is not uncommon for new members to forget the password they used for registration. As a result, when identifying on the registration pages you will get a message saying the combination of username and password does not exist. Unfortunately the 'forgot password' option on the regular logon form does not work for registrations in process.
On the registration pages you can use your email address as password. This will allow you to complete your registration. After registration is complete you can use the 'forgot password' option on the regular logon form to request a new one.