Refreshed XML Data, restarted SDC, but still got the same problem. Then, even though the log indicated it had tried both servers, I switched from US-1 to US-2. I also dismissed the pop-up telling me of the update instead of accepting it. This time, I could get the download (sorry I did two things at once so you can't pin it down). Just to make sure, my versions are:
Dark Avatar (Expansion Pack): 1.80.093
Heightmaps: 1.59.017
Also, the AutoArchive process appears to have worked on Vista now that I gave it a directory not under Program Files.
Aside: You people do great work and I wish Stardock were a public company. I'd buy stock in it instantly. Also, if the company has a few million dollars lying around, maybe you could buy TiVo and fix their latest release for them

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