[G4] copying install disc

[johnny]

hi folks,

Running 10.4.1  .  mac dual 867  . max ram

I was going to install another OS as my startup disc is gettin too 
full.... BUT my 10.4 install disc is on its last legs and won't mount 
half the time I put it in...tried different burners too.  I'm afraid to 
use it to install as I don't want a mess if it fails.....so I made a 
disc image in CCC.   Now I know I've done this before (think I did, but 
age is catching up on me) and either used the image to install (won't 
work since I get a "restart" page so it can mount the DVD as a start 
disc...and it won't copy to a DVD so I can use it as a startup disc.   
What am I doing wrong.  Tried copying from the finder (says the DVD is 
empty)managed to make an image in CCC....but image from CCC to a 
destination doesn't work as it won't find the blank DVD to copy to...and 
a couple hours of lost time trying anything I could.  I know I've done 
this in the past as I have an older backup  which of course doesn't work 
well for the past couple years either!  Any help in copying an install 
DVD 10.4 would be greatly appreciated..  Dang memory.

thanks in adv.  Johnny