Ironstrike and I ran into a snafu with the original Mechassault disc...
Seems that even if it is the original version of the game, not the Platinum Hits one, there is still a chance that it will not work. Make sure that the serial number on the inside of the data side of the disc (laser etched on the inner ring) reads: MS02301L. If it reads MS02308L, it will not work. Easy way to tell is the copyright dates on the Mechassault title screen. 2002 is good to go, 2003 is not good to work. Suffice it to say, Iron and I had the "not good" version.
More info here:
http://www.productwiki.com/microsoft-xbox/article/how-to-go-from-xbox-to-xbox-media-center-in-30-minutes.html
Currently working on my VT cockpit. Pics coming soon.
Xtag = Explodotron