Do notÂ update to QuickTime 7.4. There is a bug that may truncate filenames in iView and Expression Media, causing them to lose their references to images. If you have alreadyÂ updated Apple have older versionsÂ here.
Windows users uninstall v7.4 via the Control Panel. On Mac the easiset method to install older versions is withÂ Pacifist. The usual all care but no responsibility disclaimer applies!