does the DLC and the base game have to be on the same storage device for me to use it?

Yes it will. You can have the DLC on one storage device and the saves on another. It does not affect the game in any way.

Hey again Adam! If you are starting to have trouble with all games' DLC and it persists on multiple storage devices, there may be some kind of issue with your console. Can you try using your storage devices, account, and DLC on a different console to see
if you get the same issue? If not, you may need to send your console in for repair. Let us know what you come up with, thanks!

[quote user="Dragonball Z"]When I play the game I choose to use the HDD as my storage device but does the game access my flash drive because I keep my live account there?[/quote]

Yes, it will. Regardless of which Storage Device is Selected all will be Used for any, and/ or Profile Information or DLC.

Hey there Jano! What happens when you start up the game? Does it ask you to choose a storage device? Are the proper storage devices showing up? Do you get an error when selecting the storage device? Are other profiles having issues with loading saves? Does
your game save have a (!) icon next to it in the storage menu? Let me know, thanks!

If you are using another storage which is not the one you choose to play your Xbox 360 with, it will not work in conjunction with your new DLC.

Example: Instead of choosing Hard Drive, when prompted to choose what storage device you want to play the game with, you might choose another storage device. This storage device you have chosen may not contain this DLC.

Or is it something else? Could you please elaborate?