Back last year before the Oblivion Downloads site went down for good, I bought a couple of DLC packs, Wizard's Tower, Fighter's Stronghold, Thieves Den and KoTN (which I didn't install now because I have it on the GoTY). After I re-formatted my computer I lost the .EXEs, but figured it would be ok since I could always re-download them. Well, when I tried a few days ago I found out the downloads site was down. With Gstaff's help I was able to contact gamesas and they sent me a zip file with all of the DLC that I ordered. I'm running Windows 7, and as most of you know the DLCs won't install on 7, Vista, or 64-bit XP. For the hell of it, I tried using the .EXE (rather than Universal Extractor), and it worked just fine.
Now, this could be for one of many reasons, the first being that it was re-packed by gamesas in a manner that allows systems running these OS's to install the DLC natively. The other, which seems more likely to me, is that when they are sent, the need for online authorization is disabled because the servers are no longer online. It would seem to me that because of this, it no longer detects what kind security you have based on OS, and installs no matter what.
Either way, it works fine, and though I'd let you know
.