Can I create a bootable DiskWarrior disk?
you could try DasBoot and create a bootable disk with a USB thumb drive and a running OS, obviously not yours, maybe someone who has a similar OS. DasBoot allows you to install custom apps, and then you can boot from it and repair your disk.

I hope you have a backup. It could be a mechanical problem, which no software in the world can fix.

Do you hear strange noises coming from the HD? Is it a recent model? Maybe you could bring it to a genius bar so they can make sure it is not a mechanical failure or some other problem...