Andy_Langton - 11:36 pm on Sep 21, 2012 (gmt 0)
That's an impossibility to do with http://example.com/ simply because it doesn't exist.
By "doesn't exist" I assume you mean that there is no DNS entry. But it does exist because it's registered and you are using subdomains (www) of it.
Basically, the web (and Google) expect websites to work without a www. The message is actually a hint from Google that there is some value in creating the necessary DNS entry and redirecting without the www to the www - value enough that Google is crawling it, anyway. the simple fix is to create the redirect and then forget about it. if you don't want to do so, then as long as Google perceive value, you'll keep getting the error.