I was reading in the diskless howto that dhcpd doesn't work, only bootpd
does. Is this the case? Does this affect what I'm trying to do?

It must be me. Here's what happens in tcpdump when Windows 2000 using
Hummingbird's trial inetd server (it also provides several common
services, such as bootp and tftp) is used instead of ISC's dhcpd. 

03:38:41.751363 dhcp10.greebo.local.bootps > 255.255.255.255.bootpc:
xid:0xf6ab6acd secs:8 Y:blossom.greebo.local S:dhcp10.greebo.local
[|bootp]
03:38:49.801868 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0xcd800517
[|bootp]
03:38:49.804822 dhcp10.greebo.local.bootps > 255.255.255.255.bootpc:
xid:0xcd800517 Y:blossom.greebo.local S:dhcp10.greebo.local [|bootp]
03:38:54.801948 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0xcd800517
secs:5 [|bootp]
03:38:54.804590 dhcp10.greebo.local.bootps > 255.255.255.255.bootpc:
xid:0xcd800517 secs:5 Y:blossom.greebo.local S:dhcp10.greebo.local
[|bootp]
03:39:22.854742 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x28ff627a
[|bootp]

The exact text on the Alpha's console is:

Broadcasting BOOTP Request...
..file open failed for bootp/ewa0.0.0.5.0
bootstrap failure

Retrying, type ^C to abort...

The version of SRM is V5.4-1 Mar 18 1999 14:43:28. The PALcode is VMS
1.20-9/Unix 1.22-8. There's no ARC console loaded. The auto_action is
HALT. 

I've provided an entry either side to show a complete cycle. These are
the same results as using dhcpd on Caldera, with the exception that if
the boot prom did answer, Caldera couldn't answer back due to a lack of
tftpd. Whereas the Windows 2000 box could ship netboot via tftp if only
the prom asked for it. I'm in the process of getting a tftp server for
my Caldera box, but I don't think that's the trick.There's something
else wrong. 

But, I'm off to bed. It's late. 

Andrew