Problem with Disc Utility, please help?

I keep trying to verify disc so I can repair it, but it will not let me do so. It says that Mac HD does need repairing, but I can't get it to repair!

Oh, and the error message that pops up says this..

"First Aid failed
Disc Utility stopped verifying 'Macintosh HD' because the following error was encountered:

Filesystem verify or repair failed."

Does anyone know?

If you are trying to repair your system disk, then you will need to boot from the install media and then run disk utility.

I don't have my installation disk with me...Is there anything I can do?

In brief..no. You cannot repair a disk you are booted from.