DVD(OSX) player doesn't like working on "Spanned" Desktops, If requires Mirrored, and even then It only in on the connected screen. A solution is to close the TiBook, use a KB and a Mouse like a desktop and try it that way. DVD Player (OS9) however wants "spanned" desktops, then you have to drag the video window to the desired screen, then make full screen, and it will play on that screen.
TEG