Gotcha. I’ll go ask the maker of Instant WordPress (I’ve got a custom theme anyway). I appreciate the response – I’d been hoping this would be one of those questions where you’d just direct me to the right codex file. Alas.
Thanks so much for posting this. My eyes almost fell out of my head when I saw the “Sorry, no posts matched your criteria” message. Deactivate, activate and then index rebuild worked for me too.