Having originally failed continually with "No UDP available ...", I managed to get UDP working by first reading packet size by using parsePacket, and then modifying the Udp.read to use that packet size
int packetSize = Udp.parsePacket(); //<<<<<<<<<<<<NEW LINE HERE
// send an NTP packet to a time server
sendNTPpacket(timeServer);
...
Udp.read(pb, packetSize); // New from IDE 1.0 <<<<<<<<<<<<<MODIFIED LINE
And then, if you aren't in Chile, remember to make your own adjustment to UTC in the line which reads
t4 -= (3 * 3600L);
(the notes say this is a 4 hour adjustment, but clearly it is 3 hours)