Instructions
Power on the Xbox and sign into the same Xbox Live gamertag used to purchase the DLC content.
Navigate to the "System Settings" option of the "My Xbox" menu in the Xbox dashboard, then press "A."
Choose "Memory" from the listed options, then press "A."
Choose the storage device which contains the DLC content, then press "A."
Highlight "Games" from the list of content, then press "A."
Select "Borderlands" from the list of installed game content, then press "A."
Highlight the corrupted "Borderlands" DLC content, press "A," then choose "Delete" from the listed options.
Confirm that you want to delete the DLC content.
Re-download the DLC content from the Xbox Live marketplace. You will not have to pay for the DLC content again as any purchases made on a gamertag is saved. Once downloaded, the DLC content will work as intended.