Keynote '09 can't play slideshow again unless restarted

I am running Keynote '09 (5.0) on Mac OS X 10.6.8 on a mid-2010 MacBook Pro. Everything was fine until yesterday.

The problem is that I can play a slideshow after opening it with Keynote, but if I try to play it again, I get an ambiguous error saying: "Keynote cannot play your slideshow because an error occurred."

I would have to restart Keynote to make the exact same slideshow playable again. This happens to other slideshows I've made, too.

How should I troubleshoot this problem???? I have to make a major/high-stakes presentation in a couple days and can't afford any hiccups.

Thanks for your help.

Solution 1:

The only solution I found so far (by experimentation and searching the web) is to set the display mode to mirroring instead of presenting on a separate display. It will then let me play and replay the presentation without the error message or requiring a restart of keynote.

(Mac OS X 10.6.8 and Keynote 5.0).