Rarg

My fiance is having some problems with his powerbook G4. He went to look at it and saw that it was giving him a disk read error.
He then ran disk utility, verify disk and failed verification.
Then he tried to boot from the install disk and tried to repair the disk, and that failed.
Now the hard disk won't mount.
He got an error saying:

Keys out of order
Rebuilding Catalog B-tree.
The volume Macintosh HD could not be repaired.

Error: The underlying task reported failure on exit.


Does anyone have any suggestions?