Out of curiosity, do you have mpdscribble installed as well? One of the long shot theories I had about this problem is that upstart might be choking on having init scripts that have a common prefix in their name.
** Attachment added: "my /etc/mpd.conf file" http://librarian.launchpad.net/5593975/mpd.conf -- /etc/init.d/mpd is not run on startup https://launchpad.net/bugs/77365 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs