Difficulty Accessing DirectSong installer

I am having trouble getting the DirectSong music install to work for the Sorrow's Furnace map pack. I can get it started, but when it asks me to input an email address and password, it says my password is incorrect. I know it is correct because I have tried the same thing countless times, copied and pasted the password, and copied and pasted a password they gave me when I "forgot" my password. Is there something wrong with the installer? How can I fix it so I can license the music?