To get the serial number, go to Stardock central, go to GalCiv2 and there will be a drop down option called Dark Avatar. Right click on Dark Avatar, select register, and click the button called lookup serial number. An email will instantly be sent to the email address registered with stardock. Get the DA serial number, copy and past it into the serial number section in Stardock Central. Make sure the Product drop down menu is set to Dark Avatar (_not_ Product Subscription which it is by default) and click update. You should be able to download Dark Avatar then.