FreeBSD 6.0 freezes after root mount failure at boot

[Manu Curious]

Hi All,

While booting with 6.0, Root mount fails at boot up and It asks for manual
root mount.
But my box freezes so i can't instruct anything to the box.

So two problems here
1. root mount failure and
2. Box hang

I digged the first problem and it turns put that VOP_LOOKUP returns ENOENT 2
(in namei with LOOKUP flag) while trying to mount the correct device :
/dev/ad4s4a : ufs
Whereas my back up kernel runs fine except TTY1 hangs at times after login
or later but rest terminals runnning fine.

Any clues anybody.

Thanks in advance,

Manu