You need to register at www.usgn.de the login data of this site does NOT work at the USGN!
then you need to open the email that is sent to you and klick on the link!
then you should wait some time, after half an hour it should be done, you now can enter the login data of the USGN to CS2D. Pay attention on capslock etc, the password and the user name are case sensitive