I've used Automatic Upgrade for as long as I've used WordPress and have never had a problem. Since upgrading to 2.8.1 it no longer works.
The symptom is this: When I attempt to Automatically upgrade, the process goes fine until I click Upgrade Automatically. When I do that, the progress screen comes up and it just hangs at Downloading x.x.
Watching the directories in my Webspace Explorer, a new file is created at wp-content but it stays at size 0. I've tried changing permissions on all of the directories that I think might be involved (root, wp-content, upgrade) but nothing makes any difference.
One thing I just thought of was that I had recently uploaded the entire site again from my machine out of source control and I thought perhaps that the owner and group had gotten messed up. I can't check that from the Webspace Explorer. However, I tried the permissions set to 777 so I don't think this should have been an issue.
Any help's greatly appreciated.