Im here to tell you that clearing your cache..restarting your xbox/router blah blah blah doesnt work man. I have now downloaded that update 15 times or so now..sometimes it takes me 2 hours of trying because of the wasp error (even if im hardwired) so ill just go on about my day and check in on it frequently until it downloads. I just had to download it again a few moments ago. Its a problem that they havent fixed and probably wont fix. Good luck to you sir.

Try the steps in the following post: http://www.bungie.net/en/Forum/Post/86667001/0/0