[CentOS] mount cannot find system /dev/root

Hi, guys:

I attempt to compile a kernel on CentOS 5.3 i386 which is installed in the Virtualbox machine, and its kernel version is 2.6.18-128.el5 ,the new kernel version is 2.6.34.1

All make procedure is running ok. I can generate initrd image with no problem too. But, when I try booting this kernel, I get Kernel panic error message like these:

mount: could not find filesystem '/dev/root' setuproot: moving /dev failed: No such file or directory setuproot: error mounting /proc: No such file or directory setuproot: error mounting /sys: No such file or directory switchroot: mount failed: No such file or directory Kernel panic - not syncing: Attempted to kill init!

I don't know what is going on here!! Thanks if somebody will be able to help me!