Heres a few tips for making successful backups of xbox360 games that you own:
1) Read the tutorials posted on this site and those posted at the xbox scene forums they are intended to help people like you. So please read before asking a question that has already been covered.
2) Get a KREON Drive (tutorials will explain what this is). I you cannot or do not want to don't worry it is not mandatory, but it is highly recommended.
3) You must get a Pioneer 111D Burner for burning DL DVDs. If you already have a DL DVD Burner thats great, get the pioneer anyway, it is roughly $60.00. There is a lot of trial and error when learning to make game backups at first, and every time you try to make a backup it costs $3.00 so if your doing a lot of trial and error by hoping that maybe you could use your old DL DVD burner, don't, in the end it will cost you more, eliminate as many variables as possible and buy the equipment we recommend that you buy.
4)When burning backups there are 4 things that you need, however only 2 are mandatory:
1. An .Iso image of the game (Raw Dump via WxRipper)
2. Security Sectors ( ss.bin )
3. PFI (OPTIONAL)
4. DMI (OPTIONAL)
All of these can be obtained if you have a KREON Drive, if you do not will only be able to get number one, for the rest you will have to rely on the internet... <link removed> can help.
Mod edit: security sectors are copyrighted files, owned by Microsoft. Sites that host these ss files are potentially illegal, and therefore cannot be linked to from here. I have no problem with the site in question, I actually talk to the owner quite frequently. Just making sure this site doesn't attract the wrong attention is all (referring to a site that hosts ss files for download)
5) Good Luck!