Re: Knotehole Island
Yeah it is in the wrong section, however we do have an obligation to answer it. Before I answer though, might I suggest using the search function before you post anew.
Answer: You may not have downloaded it to be honest. It costs 800mp, and is available from the Xbox 360 Marketplace. I understand that you must have Xbox Live to download the content, but you do not need Live to play it.
If you have downloaded it (and I mean the PREMIUM version, the FREE version only lets you be there in co-op with your friends who have the premium version, although you can not do anything at all but run around and be a witness to the DLC, while being a hindrance to your friend.) then you need to be certain points through the game to get to certain points through the DLC itself.
It seems you do not have the problem of having to progress further through the game because you have finished it, so the only sensible reason is that you haven't downloaded it and simply expected it to be there, or you downloaded the FREE version. The fact that your subscription is Silver supports my hypothesis. My advice is to purchase some microsoft points and renew your subscription to xbox live using a 48 hour card, download the content and away you go.
Sorry I cant be of any help, but there is a thread made by a rather charitable member of the forums of which its purpose is to hand out xbox 360 codes. Maybe if he has any 48 hours trials in stock he could give you one if you ask nicely; if I'm right and that was your problem.
Have a good stay with the forums, and I hope you solve your problem soon