"some better know how regarding these menus and how Xbox graphic files work"
Chances of either some random with an account or a regular knowing anything about this game in particular are slim (it is not really one of the big untranslated games for the xbox), and xbox graphic files is the same answer as any modern console -- could be anything from a close to the hardware format, some game specific format or even a high level format seen outside games as well.
Looking at the text there I don't actually know if that will be graphics or conventional text -- for an older console it would almost certainly be graphics but by the xbox devs had the ability to use proper fonts (hell it is likely an error in the system menu font handler that forms the basis for a softmod or a historical version of it that you might be using).
Suggestions then as debugging the xbox is fun at the best of times would be start on corruption. You should have FTP access to the files on the hard drive (I hope you are not burning discs) so corrupt them in some useful way to see what changes. Maybe start with the fonts to see if it changes what you see there. If you can get dumps of the VRAM then maybe have a look there to see what has been loaded into it.