Just took another look at this issue. Larry had mentioned it to me some
time ago. At the time, I'd assumed it was just Google doing weird things.
In fact, it was a problem on my end (as the subject line suggests, now
fixed; read the following only if you're interested in grisly details of how.)

In theory, the search page is supposed to do nothing more than conduct
a "normal" Google search with site:projectpluto.com appended to the search
text. In other words, it does exactly what Jari suggested, except that
it spares you the few seconds of typing the "site:" specifier. I copied
all this from another site some years ago... unfortunately, I don't
remember where. It's a pretty simple way to add search to one's site.

However, it wasn't doing exactly what I thought it was doing. Prompted
by Jari's post, I realized that the search worked if you typed in the "site:"
specifier with a normal Google search. It didn't work if you just went
from my search page, even though that ought to do exactly the same thing.
In fact, I now notice that you'd get a rather bizarre URL, as if some
garbage was being sent to Google in addition to your actual search request.

It _did_ work once upon a time, so I think Google changed how this all
worked. I've figured out how to eliminate the garbage, and the 'search'
page appears to work Just Fine.

My thanks to Larry and Jari for help in figuring this out.

-- Bill