Migrate kernel 2.4 to 2.6

[Qnick <noqnick@gmail.com>]

I have a box ((Fujitsu-Siemens PRIMERGY RX300  S3) within Debian 4.0
"Etch" and 2.4.31 kernel  .
I very want upgrade it to kernel 2.6.21 but i don't know how do it.
I installed kernel package 2.6.18  from Debian distribution but after
reboot accured "kernel panic" (don't detect scsi megaraid).
After I compiled new kernel. I installed necessary package: udev,
yaird , initramfs-tools.
I tried create initrd file for GRUB used yaird. It was failure. Yaird
said "yaird error: can't open /proc/bus/input/devices (fatal):
I tried create initrd uses initramfs. It was succesfully but when i
reboot box was not succesfully because appear message:
----
Begin: Running /scripts/init-bottom ...
mount: Mounting /root/dev on /dev/.static/dev failed: No such file or
directory
Done.
mount: Mounting /sys on /root/sys failed: No such file or directory
mount: Mounting /proc on /root/proc failed: No such file or directory
Target filesystem doesn't have /sbin/init

BusyBox v1.01 (Debian 1:1.01-4) Built-in shell (ash)
Enter 'help' for a list of built-in commands.

/bin/sh: can't access tty; job control turned off
/ #

I don't know what i do wrong. :(

Thanks very much indeed for any advice or pointers to useful
information.


Regards

Qnick