I got that error message when initramfs-`uname -r`.fc13.x86_64.img was missing in the
/boot directory (partition).
That happened after a borged kernel upgrade, similar to your upgrade.
Did yours include a kernel upgrade?
did help me.
My RAID disk is /dev/md127, boot partition is /dev/md127p1, root is /dev/md127p1.
Are you able to start from CDROM/DVD?