Tunnelbroker.net users are already enrolled in the program, and should use their username/password for Tunnelbroker.net to log in.
I could not use my tunnelbroker ID/PW to log in to the certification function, but successfully did log in to the tunnel maintenance section (and of course, here) - so I know my ID/PW combination is valid. Are you certain you copied the ENTIRE database of users over to the new function?