You said you are getting an xbit....
Does that mean that your Xbox isn't currently modified?
...if that's so, then that's the problem.
An unmodded Xbox won't read anything but originals.
Btw, there are lots of good thingies online that will help you
identify your DVD drive & Xbox version.
For more info (basically anything you need to know), go to:
http://www.xbox-scene.com/