Um, that's a security feature...
That way somebody looking over your shoulder can't count how many characters your password is (which would DRASTICALLY decrease the time required to bruteforce it).
Just type in your user password and hit enter
Also, if you want to run more than one command as the root user, type "sudo su" and then "exit" when you're done. Naturally, be careful when logged in as root, as he can obliterate the entire system