As I told that ISO files are image files that needs to be burn on cds in different way .. not copying. So I am telling you to use cdrecord .. a command line , simple utility yet powerfull...
first you have to run following to know the device No. of your writer..
cdrecord -scanbus
it will give you little Nos like
0, 1, 0
0, 2, 0 etc.
not the no. in front of your writer name is listed now.. run the following command.. (you should be logged as root)
Say your device no is 0,4,0
cdrecord -v -eject speed=32 dev=0,4,0 youriso.iso
Here we are writing at the speed of 32x in cdwriter , it will eject the cd after burning it.
You can also you xcdroast , in that go to ISO9660 options section and also see its documentation.