Imac G5 Reinstall

I was trying to do a reinstall from my original disks but rec'd an error that the install failed on disk 2 and to try again. The reinstall failed several times at different points. I did finally do a reinstall of the OS only which did not require the second disk. This did work however I still could not do an install of the other apps.( same error). Does this sound like a software or hardware issue. If software, can I get replacement install disks.