Not quite sure, but sounds like you are possibly running disk utility from your main hard drive where your operating system resides. Disk utility will not be able to repair your disk while you are started up from it. Solution: The install discs your computer came with, or the Leopard install disc you have has the ability to be booted up from. Insert the disc into the computer and hold down the "c" key during startup. The system will boot from the disc and the first thing it will ask you to do is select a language. Select your language of choice and then you will get a menu bar at the top, with a drop down for utilities. Run disk utility from there and try doing a repair disk. If this does not resolve your issue you then have two options. One, you could go and buy Disk warrior to fix issues with your directory and volume structure, or you could backup your data to an external hard drive and do a complete erase and install of your Mac OS. Let me know how it works out for you.