Try restoring your license for the Taken King dlc. Once that has been completed have your friend delete his refer a friend link and then create a new one. Once he has created the new link have him send that link.
Here's a link to restoring your license.
https://www.bungie.net/en/Help/Article/12181
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This worked for me :) Thank you very much :D
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Awesome glad it worked out for you.