kernel panic - not syncing: Attempted to kill init!

i have RHEL AS 4 installed on a HP Proliant DL580 in a test
The server had Oracle installed but the database was not running at
the time.
the server was uncleanly shutdown , while rebooting we noticed there
were filesystem errors,
which dropped us to a shell for repair.i'm not an experienced user ,
but i assume i did the right thing, i did\
fsck -p at the prompt and then i quit waiting for the administrator.
we rebooted the server and we had the following error.

Decompressing Linux
umount /dev/initrd
kernel panic - not syncing: Attempted to kill init!

now the server won't boot, i did not have the time to look at the logs
and now the server is down.
I don't think i gave enough info in here, i don't know what other
information i should be providing, but anyway i hope at least some
body can explain me why or what happened and ways to avoid it?