That means your password is not correct, it has nothing to do with cd key. You are either mistyping your password or using incorrect username or password.
There are ways to change what nickname you have set for an email account with gamespy and even possibly change password by using gamespy arcade, however that trick worked month ago and whether it still works I have no idea. Info on that is :
http://digitalmindsoft.eu/forums/sho...l=1#post235145