So, here I am, trying desperately to get this to work.
A little information to consider:
I recently bought DAUE on Steam. I have Windows 7 64, I have registered both the CD keys appropriately. I had actually been able to get roughly 35 hours of playtime in. But, somehow, somewhere between shutting down my PC two nights ago around midnight, and starting it up again yesterday, I'm suddenly running into this very same issue. and it is incredibly frustrating.
So, here I am, with my game recognizing that I have the DLC installed, with my Bioware and Steam accounts in good standing, showing me as having the rights to all of the DLC in question, but, when launch DA, and log into the in-game Bioware network, I can't get anywhere due to this authorization issue, I just get to look at my myriad 26-25 hours worth of saved games, that worked no more than two days ago withou an issue.
I could go on, but that's not half as frustrating as the fact that I've gone through literally
every. single. fix. offered. With only one minor success. That whole schpiel where you go into the SteamApps folder then run the two DA programs - DAOU_UpdateAddinsXML_Steam & DAU_ServiceSetup_Steam? I did that. It worked. Then when I shut down my PC, and re-launched it today, it went back to it's old non-authorized "
obviously you've stolen this content that you just shelled out $40 bucks for you thieving terrible man you" - attempting the process again netted me no success. I went down the "services.msc" route. Ran it as an admin. Set my updater to "automatic" hit "Apply" hit "Ok" - badaboom. Everything was going peachy. Ran Dragon Age. Nothing was changed. Went back to services.msc, tried to run the Dragon Age service, everything was grayed out, when I went to close it, I got a message "This is slated for deletion" (or something along those lines). I closed the window, re-opened it, the Dragon Age service program was gone. I tried the various command prompts (again, running it as an admin), again: nothing.
As of right now, I am uninstalling, and reinstalling DAUE via Steam. I've taken my character file and placed it somewhere safe, and once I get everything installed in again, I'm going to drop the file in the proper folder, and hope for the best.
Ultimately, the thing that irritates me the most is that I managed to get 35 hours worth of gameplay in before this issue hit me, and, even after reading several explanations and reasons behind this issue, I honestly cannot comprehend how something this boneheaded can occur on such a regular basis, nor can I comprehend the best tech support available amounting to "... well, that shouldn't happen." as if I wasn't acutely aware of that fact.

Either way.