TheMadScientist - 6:40 am on Nov 7, 2012 (gmt 0)
I'm seeing it on 2 websites (on different C-class IPs), and one of them doesn't even have a robots.txt file, so the error message can't be correct.
It almost has to be somewhere you wouldn't normally look and something you wouldn't normally think it was, imo, and since you don't have a robots.txt file on one, it seems like it almost has to be a misbehaving robots tag, much like the issue I had for some unknown reason with the noarchive.
(I checked everything before I pulled the noarchive from mine, because I didn't want to, but it was the only thing that made any sense at all as a possible cause since everything else was 'wide open' for indexing and there's No Way I'd put nosnippet on a site ... It may be something completely different on yours, but there's not much else that makes much sense as a starting point for 'digging' to me.)
(I really just posted again to say, 'Hey, tedster! Been a long time since we've posted in the same thread ... Good to see you and congrats again on that little award you picked up, it was VERY well deserved.' I did try to be helpful above so I don't get snipped too hard lol)