Duke Nukem Forever demo codes only work in the region associated with your platform. Please be sure you are using an account from the same region where you received your code.
Demo codes also only work once: They cannot be associated with more than one user account on any platform.
If you have entered your code correctly following the above guidelines, please contact Customer Support by opening a help ticket within this portal. Please be sure to include your account name and demo code as well as the country where you reside.