XBMC for XBOX is not supported by Team XBMC anymore.
XBMC4Xbox is a third-party developer spin-off project of XBMC, with still active development and support of the Xbox platform. This project was created as a fork of XBMC as a separate project to continue having a version of XBMC for the Xbox hardware platform. It was not started by official members of the official XBMC project, nor will it be supported by the Official Team XBMC in any way. It started when support for the Xbox branch was officially dropped by Team XBMC, which was announced on 27 May 2010.