I'm having the same problem - did you ever find a resolution for this? I have a presentation TODAY and am desperate to figure it out and having trouble finding solution online. Any help much appreciated!
Very weird. I have a talk where movies used to play just fine (over 100's of showings). However, (and of course, given Murphy's Law, it happened in front of 300 people), the movies in this talk refused to play at a recent meeting. Of even more interest, I cannot reinsert the movies into the talk anymore. Specifically, I delete the frame image that represented the movie in PowerPoint, then use Insert>Movie as I always have, but after double-clicking nothing happens: the PowerPoint slide remains blank, the movie is not inserted, and there is no error message.
Relevant data:
The movies play just fine in either QuickTime Player 7 (7.6.3 (630) or QuickTime Player (10.0 (90.3.1)).
The issue persists in either the .ppt or the .pptx versions of the talk.
PowerPoint Mac 12.2.3 (091001)
OS 10.6.2
MacBook Pro 2.66 GHz Intel Core 2 Duo
Permissions in both the movies and the PowerPoint file are appropriate (i.e., listing me as owner with R/W privileges)
I have repaired permissions on my hard drive using DIsk Utility (11.5 (298))
As far as I can tell, my CPU is otherwise functioning just fine. Just to be safe, I have repaired the disk using Disk Utility.
Any advice would be greatly appreciated! Thank you!

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