So, you brought home 10.1 to watch DVDs on your PowerBook, to no avail? As always, Apple KnowledgeBase to the rescue:

KBase 60895: DVD Player 3.0, included with Mac OS X 10.1, does not work with external monitors or televisions connected to PowerBook computers.

KBase 106479: DVD Player 3.0 is not installed on PowerBook (FireWire) computers unless a DVD-ROM drive is in the media bay when you install Mac OS X 10.1.