ALL of the Black Ops Map Packs are REGION LOCKED. That means you must meet certain criteria in order to get access to download them. If you do not meet ALL of the criteria then you will encounter issues downloading and accessing the content.
Account Region+Game Disc Region+Actual Live in Region=ALL must match
Im English, have an English account but now live in Holland.
To get the map packs i had to create a Dutch account and download them from the Dutch marketplace. However the version i have is [EN] and the map pack on the Ducth marketplace is also [EN]. So it might be worth checking the german marketplace to see if it
comes up as [EN]. You should have no problems if it is.
There was a sticky thread in these forums about this exact topic, but that was in the old forums and I am not sure where its at now. I am not exactly sure about your situations, but i think your Xbox or game and DLC have to be from the same country, but
not totally sure. Maybe someone will step in and help more.
I have exactly the same problem, but am in france, I even contacted Microsoft and the told me i won't be able to purchase "anything" in the English market place with a French ip. I can guarantee that this is lies as the nite before being told that I ad purchased
content for other games and have since downloaded content for other games. I personally think this is extremely ignorant of Microsoft, activision and also treyarch to think that just because u live in one country that you will be purchasing the game from that
country and also fluent enough in that language to be able to play the game. I have since asked Microsoft and activision how to deal with this and also how I lodge a complaint with regards to the matter.
As for resolving it Microsoft told me I would have to set up a French gamer tag which I'm guessing will involve buying a French version of the game too.