I found this archived post that may shed some light if you are having issues playing the new Annihilation Map Pack:, its from Support, about Escalation, but the principle is the same:[quote]Hey everyone—
I know everyone is super excited about the release of the Escalation pack on LIVE on 5/3/11 but there are some very important things to keep in mind.
The Escalation Pack Is Tied To The Language Of Your Call of Duty: Black Ops Disc
Put into it’s simplest terms, if your copy of Call of Duty: Black Ops is in English, you must use a download the pack in English as well. Don’t worry, we’re going to be clear in our offer descriptions about which language you are downloading and only make languages available in Xbox LIVE Markets where those languages are sold. If you, lets say, live in Canada where both French and English are supported, if you download the pack in a language other than your disc it will not work and you will receive an error (‘The content you are trying to load is from a different region’). Of course, to avoid this—check the offer names and descriptions closely!
If you happen to have imported the disc from a different country and use a LIVE account where you live, you may also run into issues as the language of that disc may not be available. For example, if you live in the US and brought a copy of Call of Duty: Black Ops home from France, you will not be able to buy the French version of the pack on your US Xbox LIVE account as that version of Escalation is not sold in the US. The only solution is to buy a copy of Call of Duty: Black Ops locally that supports the languages supported in the country of your LIVE account.
Be Careful On Marketplace.Xbox.Com Links
All of the above being said, every time we release content it can take a few hours for it to show up in everyone’s version of the marketplace on their Xbox 360 while it may appear a bit sooner on the Xbox.com Marketplace. Usually a ton of folks will flood the forums with ‘BUY IT FROM HERE!!!’ links which may be a regional (such as a Japanese) version of the offer.
It is VERY important that you ONLY download the content from the correct region of your marketplace—while you may get to the download a few minutes earlier, you might end up on the wrong link and end up with the wrong language on your console—and therefore not be able to use the pack with your copy of Call of Duty: Black Ops.[/quote]