So, I've done the standard delete, clear cache, restart, redownload fix. Numerous times. But still every time that I try to do the mission in the DLC, I get a "disk unreadable" error. After re-downloading and restarting the game, I get a prompt to update for the game, and it will not start if I choose not to update.
The weird part is that it seems only part of the file is corrupt, as I am able to recruit and talk to the character just fine. I had a similar issue with the Zaeed Massani pack, but that WAS resolved with the normal method.
I purchased this item with points on november 2nd (I believe).