Additional information: apparently no one involved in developing the Ethernet Library has tested communications with web servers other than Apache. The library as-is will not communicate with lighttpd. Phil's modification above does allow communication, you will need to take care to render each line into a complete string before trying to println() it; multiple print() commands per line will not work.
So now I need to figure out why the Ethernet library hangs after four connection attempts at 5 second spacing, even with stop() command after each connection. At this point I know the connection idles in the FIN_WAIT state for less than a second up to 20 seconds. If another connection is attempted during this time, apparently the library makes a new one...it's limited to four. The Client::connected() function does not address this at all.