DOC2000 grub boot problem

[lhl]

I had install the grub in DiskOnChip 2000,and the grub info show when boot
I use the Dformat write the grub_firmware to the DOC,the size of grub_firmware is 98304 bytes
I had Partition the nftla with one partition nfla1
use the fdisk /dev/nftla use t to change the ID to 83(linux)
then mke2fs /dev/nftla and mount it on /mnt,cp the bzImage to the /mnt/boot/vmlinuz-doc
cp the menu.list to the /mnt/boot/grub/
menulist:
timeout 10
default 0
title DiskOnChip Boot
kernel (dc0,0)/boot/vmlinuz-doc root=/dev/hda4

problem begin when start the grub
it showes such messages:
Attempting to open /boot/grub/menu.list on driver 0x80 XXXX
....

and once I don't know what I had done,it goes to
grub>
and I try 
grub> kernel(dc0,0)/boot/vmlinuz-doc root=/dev/hda4
Loading kernel image......
	Linux-bzImage,setup=0xa00 size=0xec7a4

what's the problem with my doc?