My Software Update is broken. I had tried to set it to update from my OS X server (server.local) (instead of pulling from Apple) to save bandwidth, but was never able to get it working. Now when I run Software Update, I get:
The Software Update Server (server.local) is not responding.
Check to make sure your network connection is operating normally. If there are no issues with your connection, contact your network administrator for assistance.
I've tried resetting it back to the default location by doing:
defaults write ~/Library/Preferences/com.apple.SoftwareUpdate CatalogURL "http://swscan.apple.com/content/catalogs/index-1.sucatalog"
defaults write /Library/Preferences/com.apple.SoftwareUpdate CatalogURL "http://swscan.apple.com/content/catalogs/index-1.sucatalog"
but it still gives the same error.
I've also tried using the Software Update Enabler which had no effect.
I'm was running Leopard when I first encountered this problem. I've since upgraded to Snow Leopard but that had no effect on this issue.