Ah, yes. There are differences in the 1.8.1 version of search.php. I don't recall you telling us that we had to overwrite that file to upgrade, but the old memory ain't what it used to be.
Next question about that: I am now getting the "View RSS for this Page" link, but when I click on it, nothing happens. The RSS document is on the server because I checked that. Any idea what the problem could be?