That is precisely what I had done. I thought I had remembered to remove the redirect line after I was finished with the article. Apparently, I had not. I'm not sure why I didn't get this error when I had installed other recent iOS updates, but at least I knew why I was getting it now. After deleting the redirect line in the hosts file, I attempted to restore my iPhone one more time. Success.
What's the moral of this story? I can imagine a few suggestions from readers, none of the them especially flattering to me.
One might be: "Serves you right. That's what you get for messing around with jailbreaking. Don't expect any sympathy from Apple."
Another might be: "Read your own article. It clearly states you need to remove this file before attempting to update or restore in iTunes. You forgot. It's not Apple's fault."
Still, I am not ready to accept the entire blame for my update hassles. Apple could do better as well.
First, as Apple indicates, there are potential causes for this problem that are not related to jailbreaking. So let's not lay all of this on the jailbreaking doorstep.
Second, I fail to understand why Apple can't offer more informative alert messages. Simply saying that you have a 1013 error is of no value to the typical user. At the very least, the message could include a link to the support article that gives the additional information. Otherwise, Apple sets up users to have no immediate recourse other than panic.
Finally, why have this error message pop up at the point in the update process where the iPhone has been erased and forced into recovery mode, requiring a time-consuming restore? Why not check for these errors before going down that one-way street? That way, the process could exit gracefully, with the iPhone not updated but at least still functioning.