[CentOS] kickstart, no dhcp reply received.

I'm trying to kicktart a CentOS 4.3 x86_64. However, anaconda is
unabled to do dhcp, complaining about"no DHCP reply received".  While
tailing the log on the dhcp server, I clearly see a request come in
and address is offered.  This same machine kicks fine with CentOS 4.1
(32-bit).  Since anaconda could potentially use a different NIC (this
system contains 2 NICSs), I've tried plugging both interfaces into the
kickstart network (I've seen interfaces swapped before) as a test.

I know that the CentOS 4.3 x64 setup I have works fine because I can
kick a different hardware with it.

Any idea what else to check for?  Could it be that the e1000 driver in
CentOS 4.3 x64 is older than the CentOS 4.1 driver?

Any help is appreciated.