OK so here's a summary of the situation. I have a single ISO image which is a bootable Linux Mint install (ISO file is a little over 900MB), standard ISO 9660 format. I have 3 DVD-R disks (all from the same lot) written with this image:
1) Written on Windows 7 SP1 laptop using the built-in ISO image writer
2) Written on Windows 7 SP1 laptop using BurnAware
3) Written on a Linux Fedora 15 system (system B below), using Gnome Baker or something like that...
I have 4 computer systems
A) Windows 7 S1 laptop
B) Linux Fedora 15 system
C) A blank system (we'll call System C) which doesn't have an OS on it yet but has a USB connected DVD-RW drive
D) Another blank system (we'll call System D) which doesn't have an OS on it yet, but has a built in DVD-RW.
System A can read disks 2 & 3, but not 1.
System B can read disk 3 only
System C can read (boot and install from) disk 3 only
System D can read (boot and install from) disks 1, 2, or 3.
Interesting... I'd be convinced it is a difference in disk alignment, except the very system that wrote disk 1 can't read disk 1.