Hello,
Sorry to hear you are having trouble.
Hi im also having the same issue with getting some of them to activate. It works when i install the program then enter the key in the program it self but i cant add them to my account online via "Register Product" under the account management option. It just says
The registration page is only, has only ever been, for registering old CD games post purchase - it is not for software.
Steam keys received through Humble cannot be registered, nor will they ever appear, on your Stardock account unless they were purchased on our store (only games are this way).
Any Stardock key received from Humble will not show on any Stardock account after it is activated for the first time. After the key has been activated, it is forever tied to that email.
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Sean Drohan
Stardock Customer Service Manager