cannot log in to alioth in order to register for debconf

[koanhead]

I would like to attend DebConf 2014. The page at http://debconf14.debconf.org/ says:

"f you want to attend DebConf14, please fill out the registration form. " The word "form" is a link which points to https://summit.debconf.org/debconf14/registration/, which redirects to the monster url cited in the next paragraph:

https://sso.debian.org/sso/acs_error?DACS_ERROR_CODE=902&DACS_VERSION=1.4&DACS_FEDERATION=DEBIANORG&DACS_JURISDICTION=DEBIAN&DACS_HOSTNAME=sso.debian.org&DACS_USER_AGENT=Mozilla%2F5.0%20%20X11%3B%20Linux%20x86_64%3B%20rv%3A24.0%20%20Gecko%2F20140319%20Firefox%2F24.0%20Iceweasel%2F24.4.0&DACS_REQUEST_METHOD=GET&DACS_ERROR_URL=https%3A%2F%2Fsso.debian.org%2Fo%2Fauthorize%3Fscope%3DOPENid%2Bemail%2Bprofile%26state%3DdZUk5x0AEGTlUI9r1zpBdzN1SEhTzXb7%26redirect_uri%3Dhttps%3A%2F%2Fsummit.debconf.org%2Fcomplete%2Fdebian-oauth2%2F%26response_type%3Dcode%26client_id%3DHUL%3D1jMcEEjGjYJecEI%40xuJKF2N8i!LmVXpaeusm%231487733681751925193#22392705319008965957

This page does not permit me to log in to Alioth. When I try, I get the error message:

"Authentication failed
Invalid authenticating information"

I'm quite sure that I'm using the correct login information, as I'm able to log into Alioth from https://alioth.debian.org/account/login.php with the identical information.