Making a bootable CD-ROM or DVD is more than just copying files, you have to burn the disk in a special way.
I don't know how you are booting into DOS in order to run Ghost. I use a bootable floppy with CD-ROM support. (Things are easiest if you have a floppy drive on your computer). That way I don't have to worry about creating bootable CD/DVDs myself.
You burn the DOS Ghost.exe program onto the first disk along with the first (gho) file, and if there is room, the first .ghs file. (you can make sure there will be room by adjusting the gho/ghs file size when creating the image) Then, when doing a restore, you can put the first (or only) disk with your Ghost image in the DVD drive, and boot from the floppy. When the DOS prompt appears, just run Ghost.exe off the CD or DVD and select the .gho file, and it will do the rest, asking you to change disks where necessary.
Or, you can do it another way. You can ask Ghost to burn the images directly to DVD(s). If you do this it will ask you if you want to make the (first) DVD disk bootable. If you answer "yes", it will request that you place a bootable floppy disk in the floppy drive, and use the files off that in creating the bootable CD/DVD.
Furthermore, if you have Ghost installed in Windows, there is a Ghost Boot Wizard in your Program Files\Symantec\Ghost folder which will create a boot floppy for you if you need it.