Go to "System Setting => Console Settings => Language and Locale". I'm not sure if it works. And try to disconnect Xbox from Internet. Maybe it checks your IP settings... I'm really guessing now.
What does it say when you're launching the game? or it doesn't start at all? I'm just curious about...
and changing your region settings in your Xbox 360 won't solve the problem? I mean I have PAL Xbox and it works for me. And as far as I know "region locked" means that you can't download the game/demo from Xbox MarketPlace. Am I missing something?
So you've burned the game onto a dvd? And it has the following folder structure: "Your_dvd_drive_letter:\Content\0000000000000000\58410A8D\000D0000\F91CEC8666B19773E50DE06E223AF430A1C4965E58" ? And still doesn't work?
Try to put the game on a usb drive or burn it onto a dvd using udf file system.
After downloading it you should get a rar archive "DeadRising2CZ.rar". Extract it with WinRar and you get a folder structure "58410A8D\000D0000\F91CEC8666B19773E50DE06E223AF430A1C4965E58". Then read the information in the first post.