iMac C2D Hard Drive Reparing Error

[CiBoys]

Verifying volume “20”
Checking HFS Plus volume.
Checking Extents Overflow file.
Checking Catalog file.
Checking multi-linked files.
Checking Catalog hierarchy.
%)
Checking Extended Attributes file.
Checking volume bitmap.
Volume Bit Map needs minor repair
Checking volume information.
Invalid volume free block count
Invalid volume free block count
uld be %@ instead of %@)",2)
27416926
27410467
Volume Header needs minor repair
The volume 20 needs to be repaired.

Error: The underlying task reported failure on exit


1 HFS volume checked
Volume needs repair

and i can't click on the "Repair Disk" button I dont know why... Do i have to format my disk or is there a way i can repair it?

 

[Ramsos]

You need to boot up from the system disc that came with the iMac. Insert it and restart holding "C" on the keyboard and you can use the disk repair utility to fix the Hard Drive. You can't repair a hard disk when it's in use.

 

[MIDI_EVIL]

...Or use target disk mode.

Rich.