Kernel panic

Hey. I'm running Kubuntu linux, and I wanted to compile my own kernel so I'd have the right sources and everything to install some other stuff. So, I downloaded kernel 2.6.12, used the config file that Kubuntu sticks inboot, made an initrd.img with "mkinitrd -oboot-initrd.img-2.6.12", fixed grub, and tried to boot into the kernel. It didn't work. With the initrd.img specified, it gives me a whole bunch of these:

ERROR: Module X does not exist inproc-modules

(Where X is one of a few screensfull of modules) And then this:

pivotroot: No such file or directory sbin-init: 428: Cannot open dev-console: No such file Kernel panic-not syncing: Attempted to kill init!

Ok, so I tried it without the initrd.img and it only spits out:

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

I don't know what's going on. Ext3 and Ext2 are built-in to the kernel, so I know it's got to recognize the fs right? And I made it from the old config file that ships with Kubuntu, so I don't know what the problem is. Here's the entry in grub's menu.lst

breastle Kubuntu, kernel 2.6.12 root (hd1,0) kernel vmlinuz-2.6.12 root=-dev-hdb5 ro quiet splash savedefault boot

Any ideas? Thanks!