Well this post sounds kinda suspicious since you have an xbox iso but don't know how to use dvd2xbox. Anywho I will pretend you didn't pirate the game.
1. Dvd2xbox is a program that lets you rip dvd xbox games or movies to your xbox hdd. It does not put them into iso form.
2. There is no real installation of a game. You just put the game files on the hdd and you run the main .xbe file (usually default.xbe).
3. Programs like IsoBuster can't open xbox iso files because they arn't regular iso files. They are xiso (xbox iso) files.
4. There are many programs that allow you to manipuate xiso files. Check out this
page for more info on xiso tools. I recommend Craxtion