I am seeing similar issues. So far I've seen it on an iMac Core Duo system with 10.4.11 and Office 2004 11.3.9. I've read several things that its related to an OpenGL update in 10.4.11, is that correct? It may explain why it doesn't affect all models. I couldn't reproduce it on my MacBook Pro santa rosa. The crash happened with a freshly logged on user account.
We are seeing the same issue on a freshly-imaged 10.4.11 MacBook Pro in PowerPoint 2004 -- the app quits unexpectedly when entering full-screen slideshows, regardless of the presentation in use. There are additional reports of the issue on the Macenterprise mailing list, and here:
<http://discussions.apple.com/thread.jspa?messageID=6033304>
Some have suggested that a subsequent update to 10.4.11 corrects this issue, but I can't vouch for that. You might try running Apple's software update on the affected machine, or (if you're feeling daring) swapping the graphics libraries with a 10.4.10 machine as described in the thread above. In my case, I have advised the user to show her presentation in Keynote for now.
I should be able to check the status of our affected machines on Monday and advise if the software update clears the issue.