iDefrag comes on a bootable disk. If it won't boot, you should contact the makers and arrange for an updated copy that will boot from your Mac.
But whether you do that or not, booting from a DVD is a *painfully slow* way to boot your Mac. A much better method (cheaper as well, minus the cost of the drive) is to have an external drive (which you should have for doing backups anyway) and create a "bootable clone" using a program such as
SuperDuper or
Carbon Copy Cloner. Then you can boot from the clone and run iDefrag.
I personally prefer the "clone-test-erase boot disk-clone back" method, as it costs me nothing, but since you already have your paid copy of iDefrag you might as well use it.
I hope that answers your question. Sorry if I sounded evasive before, I just couldn't understand what you were getting at. Booting off a disk and trying to run iDefrag from the boot drive wouldn't have worked anyway.