[Gordie]

My 6 month old G5 running 10.3.5 (recently updated) will not allow me to install any new programs, I tried to run disc utility to repair the HD however it will not open either. All programs currently installed run fine, do I have to re-install OSX to get this thing fixed or is there something else I can do?

[Nobody]

First put in your OS X install CD and see if you can repair permissions from there. Post back if you can or can't. It is always best to repair permissions using disk Utility on your Mac instead of the CD, but in your case I would try the CD first. If it works, then see if you can open Disk Utility and repair the permissions again.
You can also repair the hard drive from the disk too.

[Grant_G]

I'm assuming you mean Disk Utility won't let you repair the drive, not that you can't open the application. Disk Utility can't repair the startup drive. You can only repair permissions from it, but that's likely what your problem is anyway. Always repair permissions following any installation or update that goes through an installer process -- as opposed to just drag and drop.
If I'm wrong and you cannot open DU from the hard drive, then definitely follow Lori's advice and run it from the CD, then rerun it again from the drive once you can use it.
G