Sorry if this is an FAQ, but I searched everywhere I could first

I worked my way through the Diskless HOW-TO, and have been able to get an
IPC and IPX to boot to single-user from the same host machine.  But when I
try to boot the Mr. Coffee, it gets an address from DHCP, and loads down
bootjs.net (symlinked from C0AS010A in my case), but that is as far as it
gets.  The screen on the Mr. Coffee shows:


--- Begin Screen ---
JavaStation
OpenBoot 3.11.0, 64 MB memory installed, Serial # 8907606
Ethernet address 8:0:20:87:eb:56, Host ID: 8087eb56

>> NetBSD/sparc Secondary Boot, Revision 1.14
>> (jmc@faith.netbsd.org, Wed Mar 23 01:03:20 UTC 2005)
Patching OFW for SUNW,JDM1
cpu: creating node
eeprom: adding "model"
le: deleting bogus "interrupts"
su: adding "interrupts"
Booting netbsd
Can't open device `'
Cannot load netbsd: error=6

device[] ("halt" to halt):

--- End Screen ---

Now, when I try to boot an IPX in the same way (with boot.net of course) it
gets the root-path from the server and can load up.  It looks to me like
this information is not being either requested or processed by bootjs.net on
the Mr Coffee.  The table entry in dhcpd.conf for the machine looks like:

# Configuration created for booting JavaStations
#
ddns-update-style none;
#
allow bootp;
authoritative;
subnet 192.168.1.0 netmask 255.255.255.0
{
	range 192.168.1.100 192.168.1.254;
	option broadcast-address 192.168.1.255;
	option domain-name "ptyesg2.tld";
	option domain-name-servers 192.168.1.2;
	option routers 192.168.1.1;
	option subnet-mask 255.255.255.0;
}
#
group
{
	option broadcast-address 192.168.1.255;
	option domain-name "ptyesg2.tld";
	option domain-name-servers 192.168.1.2;
	option routers 192.168.1.1;
	option subnet-mask 255.255.255.0;
	#
	host java01
	{
		hardware ethernet 08:00:20:87:eb:56;
		fixed-address java01;
		option host-name "java01";
		filename "C0A8010A";
		option root-path "/export/java01/root";
	}
}

And the relevant part of /etc/exports looks like:

/home -maproot=root:wheel -network 192.168.1.0 -mask 255.255.255.0
/export/java01/root -maproot=root:wheel java01
/export/java01/swap -maproot=root:wheel java01
/export/java01/usr -maproot=root:wheel java01

I have a bunch of these machines I want to bring back to life, but I can't
see what I am doing wrong?  Any suggestions?

Thanks in advance