i understand what you are trying to do,
u have some .iso's, probably about 700MB each right?
u want to put them on a DVD, not a CD-R. So that you can fit MORE Onto the disc.
WELL, i know that when i get my linux installers, i look for DVD specific ISO's..
u can't just put an ISO meant for a cd-r, onto a dvd.
if you carouse some linux distro download sections, you will see the dvdiso's im talkin about.
here is an example:
Downloading the ISO Images
The ISO images are located at the following URL:
http://download.fedora.redhat.com/pub/fedora/linux/core/4/i386/iso/
http://download.fedora.redhat.com/pub/fedora/linux/core/4/x86_64/iso/
http://download.fedora.redhat.com/pub/fedora/linux/core/4/ppc/iso/
To install from a DVD that you plan to burn, download the following ISO image files:
For x86-compatible (32-bit): FC4-i386-DVD.iso (sha1sum: 2f151a7329846da685c2a72fcb40eba3e8a355a0)
For x86_64 (64-bit AMD64, EM64T): FC4-x86_64-DVD.iso (sha1sum: 2f166c7cff4e7334744d48e642b3287693d982ed)
For PowerPC (32-bit and 64-bit Macintosh, 64-bit pSeries): FC4-ppc-DVD.iso (sha1sum: 7bb39bb530ad0954f8faea585ebea23f40d5a010)
Note: If you are using HTTP or FTP to download, some download clients cannot handle the DVD image because it is larger than 4 gigabytes. Please refer to the documentation of your download client for details.