I figured out the problem!
I needed to save my dummy roster on the Xbox with the same filename as the one I am replacing it with (i.e. your updated roster jan2011). Earlier, I was just making a generic name on xbox and changing it later to match with Modio, but turns out I have to have it match when I initially make the roster file on the xbox. Didn't know that haha.
Thanks so much for your help.
What's the difference between your file on this thread and the other one you created?