Sorry if this has already been answered, but it would appear that the CD key I got with L&G follows the standard Steam format of having five 5 character long groups, whereas the Paradox registration form only allows for six 4 character groups. I tried the usual method of filling it in and dropping the final character with no success. I will try again in case I miss typed, though there is no indication on the form as there is with other games that I should have the Steam format registration key.
Same issue here too.