I found the problem!
I was using the incrrect DNS numbers in '/etc/dhcp3/dhcpd.conf'
at 'option domain-name-servers'...
Network Boot worked like a charm to load Ubuntu onto a new HD!
For later referrence this is a very easy and complet Network Boot
tutorial:
http://mywheel.net/blog/index.php/ub...twork-install/
Thank you everyone