Apple has released iMovie 9.0.8 for Mac OS X 10.7.4 or higher. The upgrade improves stability when using third-party QuickTime plug-ins such as Perian, Flip4Mac WMV Player 3.0 and other non-Apple extensions.
iMovie 9.0.8 also sports MPEG-2 previews during camera import, and resolving an issue with missing audio from some AVCHD and MPEG-2 imports. Mountain Lion users can obtain the update via the Mac App Store and Lion users can grab it via the Software Updates component of the Mac OS X System Preferences app.