mysterious kernel panic at start up and it's workaround

[Aaron Brashears <gila@gila.org>]

I upgraded my kernel using the prepackaged 2.4.17 pentium pro
kernel. On bootup, I get the following message:

Request_module[block-major-3] Root fs not mounted
VFS: Cannot open root device "303" or 03:03
Please append a correct "root=" boot option
Kernel panic: VFS: unable to mount root fs on 03:03


The funny thing is that if I use the append root=/dev/hda3 in
lilo.conf, it doesn't work. However if I load the debian rescue disk
and specify root=/dev/hda3, the kernel boots fine. Why won't it just
boot? 

I've partitioned my drive to use /dev/hda1 as /boot and /dev/hda3.