help: self compiled kernel reboot problem: unable to mount root fs on unknow

["weiyun lv" <lvweiyun@hotmail.com>]

VFS: cann't open root device "hda2" or unknown-block(0,0)
Please append a correct "root=" boot option.
Kernel Panic -not syncing: VFS: Unable to mount root fs on unknown 
-block(0,0)

hello, I am a newbie and I just installed sarge and want to work on it, 
trying to write a device driver for an IO card. Today I
1. download kernel source 2.6.10 from kernel.org
2. reconfig the kernel, disable module versioning, and enable most of 
kernel-hacking options.
3. use the following command to recompile and install the new kernel:
 # make-kpkg clean
 # make-kpkg --append-to-version=.0901 kernel-image
 # cd /usr/src
 # dkpg -i kernel-image-2.6.10.0901_10.00.Custom_i386.deb
4. after installation the menu.lst reads as: kernel 2.6 boot with the above 
error message and kernel2.4 can boot successfully.
===============
title		Debian GNU/Linux, kernel 2.6.10.0901
root		(hd0,1)
kernel		/boot/vmlinuz-2.6.10.0901 root=/dev/hda2 ro
savedefault
boot

title		Debian GNU/Linux, kernel 2.4.27-2-386
root		(hd0,1)
kernel		/boot/vmlinuz-2.4.27-2-386 root=/dev/hda2 ro
initrd		/boot/initrd.img-2.4.27-2-386
savedefault
boot
==================

PS: 1. I have met this problem on ubuntu too and haven't resolved it yet.
2. maybe something wrong with my kernel configuration and can anybody 
provide some material for this.
3. I use ext2 file system.