HELP! DHCP & Comcast

My old cable modem seized up and died a while back and
Comcast replace it with an RC DCM425c.  I hooked it up
to an XP system (doctor says I'll recover after a while ;)
and entered the account number and got the thing configured
... I think?

Then I did the same thing I used to do with the old modem:
I powered if off and connected it to my NetBSD system (3.0.1).
When I run dhclient <cable interface> it doesn't get connected.
I can run tcpdump -i <cable interface> and see lots of arp traffic
going by so I think the equipment is working but, I keep getting
this in /var/log/messages:

Oct 21 18:27:42 bigbox dhclient: No working leases in persistent database - sleeping.
Oct 21 18:34:58 bigbox dhclient: DHCPDISCOVER on tlp1 to 255.255.255.255 port 67 interval 3
Oct 21 18:35:01 bigbox dhclient: DHCPDISCOVER on tlp1 to 255.255.255.255 port 67 interval 8
Oct 21 18:35:09 bigbox dhclient: DHCPDISCOVER on tlp1 to 255.255.255.255 port 67 interval 13
Oct 21 18:35:22 bigbox dhclient: DHCPDISCOVER on tlp1 to 255.255.255.255 port 67 interval 20
Oct 21 18:35:42 bigbox dhclient: DHCPDISCOVER on tlp1 to 255.255.255.255 port 67 interval 10
Oct 21 18:35:52 bigbox dhclient: DHCPDISCOVER on tlp1 to 255.255.255.255 port 67 interval 7
Oct 21 18:35:59 bigbox dhclient: No DHCPOFFERS received.
Oct 21 18:35:59 bigbox dhclient: No working leases in persistent database - sleeping.


ifconfig of <cable interface> shows:

: ifconfig tlp1
tlp1: flags=8b43<UP,BROADCAST,RUNNING,PROMISC,ALLMULTI,SIMPLEX,MULTICAST> mtu 1500
        address: 00:a0:cc:3a:d9:52
        media: Ethernet autoselect (100baseTX full-duplex)
        status: active
        inet 0.0.0.0 netmask 0xff000000 broadcast 255.255.255.255
        inet6 fe80::2a0:ccff:fe3a:d952%tlp1 prefixlen 64 scopeid 0x3

I have a DSL line that should be my default route but, I changed the
default to 0.0.0.0 and started up dhclient.  It still doesn't want to
connect.

Can anybody tell me where I'm going wrong with this??

TIA,
Paul