If your machine(s) can boot from usb, then give Unetbootin a shot. It is in
the repositories. It works well with Ubuntu (but not all distros). A 2 GB
usb key will do for any of the *buntus, but I prefer a 4 GB as I use it for
multiple distros and some fill a DVD.

The trick in making it work is to have an empty key (use Gparted to format
to FAT 32) and to have it mounted BEFORE you open Unetbootin. Otherwise it
will not be able to locate the key. It is faster and does not waste disks or
have burning issues. If you can't or don't want to try usbs, then you might
want to burn at a slower speed, try different media brand and check your
DVD/CD drive.