Dragon Age:Origins DLC -The Stone Prisoner download failed

I wish I could offer a solution. However, I can at least offer a workaround. It sucks that it should be necessary, as EA/Bioware has a responsibility to provide a simple fix. But if you really want to play, this should work. I've known about this for a while, but a minor goof on my part made me think that it wasn't working.

1. Go to social.bioware.com and login using your EA/Origin account.
2. Go to https://social.bioware.com/user_entitlements.php

This page should list every piece of Bioware DLC registered to your account. For the PC, it also provides download link. There are 2 kinds of PC downloads here: .exe files and .dazip files. For .exe, obviously you just double click them. They're standard installers that should find DA and install the content. For .dazip,

1. Find the daupdater.exe application. It is usually located under \bin_ship in your Dragon Age folder (for example C:\Program Files\Dragon Age\bin_ship\daupdater.exe). Double click on it to open it. 
2. Click on "Select DAZIPs". Navigate to where you have saved the .dazip file and open it. 
3. Now the .dazip file will appear on the Install tab. Select it on the list and click "Install Selected."

Do it for every item on your account, and you should be golden. Next time you start the game, all your content should show up under installed contet. Note that you WILL still have the stupid red exclamation point under the downloading tab, which will still list all you content as "download failed," but it should also be listed under the "installed content" tab, and be functional in-game.

The If it doesn't, or it shows up as unauthorized, make sure that the updater service is running. To do this, close the game, hold down the Windows key + R to bring up the run dialoge. Type services.msc in the run box. This will bring up your winows services. Scroll down to "Dragon Age: Origins Updater" and start it. Then run the game again. Note the update service has alway been a finnicky pain in the butt, so if you later start the game and get a message saying you need to log in with an account that has bought this content, it means you need to restart the service again.

This SHOULD work for you. If it does, please mark my answer as the solution so I get points.