E_ADEPT_CORE_USER_NOT_ACTIVATED - New iriver story HD

Hi

My son got a new iriver as we are going on a trip on sunday. He loves reading books so I thought it could be a good idea with this device as we could download a lot of books from our library. However we don't get it to work. We only get an error message : E_ADEPT_CORE_USER_NOT_ACTIVATED

What is wrong? We have logged in with the same email and code on both my MacBook as his device? Nothing works!

Would love getting some help. And please bare in mind that I´m new on this so it need to be super clear advices
Thanks for your help

Johanna