Ok, in the last two or three weeks I've been having exactly the same problems with iPhoto and my FujiFilm S5500 camera. Possibly it was since I installed Mac OS X 10.4.9, I'm not sure. But now I think I have found the solution. And the key came when I went to the web site:
Perian - The swiss-army knife of QuickTime� components
(( My installation is a iMac PowerPC G5 with Mac OS X 10.4.9 & QuickTime 7.1.5 ))
where is says: Installation Tip: Please consider removing obsolete QuickTime Components.
So I trashed the whole of the directory /System/Library/QuickTime which contained the following files:
QuickTimeComponents.component 28 March 2005
QuickTime3GPP.component 28 March 2005
QuickTime Updater.app 28 March 2005
QuartzComposer.component 21 March 2005
QuickTimeVR.component 28 March 2005
QuickTimeUSBVDCDigitizer.component 21 March 2005
QuickTimeStreaming.component 28 March 2005
QuickTimeMPEG4.component 28 March 2005
QuickTimeMPEG.component 28 March 2005
QuickTimeIIDCDigitizer.component 28 March 2005
QuickTimeH264.component 28 March 2005
QuickTimeFireWireDV.component 28 March 2005
AviImporter-r7 (ppc).component 25 March 2006
XviD_Codec-r58 (ppc).component 25 March 2006
When I had done this, not surprisingly QuickTime told me is couldn't open files.
Then I installed the latest version of QuickTime 7.1.6
which put the following components in the system directory : /System/Library/QuickTime
QuickTimeComponents.component 28 April 2007
QuickTimeH264.component 28 April 2007
QuickTimeIIDCDigitizer.component 28 April 2007
QuickTime3GPP.component 28 April 2007
QuickTimeMPEG.component 28 April 2007
QuickTimeFireWireDV.component 28 April 2007
QuickTimeStreaming.component 28 April 2007
QuickTimeMPEG4.component 28 April 2007
ApplePixletVideo.component 21 March 2005
QuickTimeVR.component 28 April 2007
QuickTime Updater.app today
Now it plays the videos from my digital camera.
To play other videos I then needed to I rescued the following components from the trash and put them back in : /System/Library/QuickTime
AviImporter-r7 (ppc).component 25 March 2006
XviD_Codec-r58 (ppc).component 25 March 2006
Now it all works again and I can watch videos from my digital camera and videos downloaded from Azureus, and I didn't need to install Perian.
Hopefully this technique will be of help to someone.