Confirmed. (Ouch, sorry about that.) We noticed that happening for PCM audio a few days ago, too. Scheduled to be fixed in Vuo 0.9.0.
In the meantime, I know offhand that if you encode the movie using FFmpeg with the h.264 video codec and the Vorbis audio codec inside a QuickTime container, it plays just fine.
(In order to support a wide variety of movie formats, to work around QuickTime’s multithreading and performance issues, and to work around QuickTime’s incomplete 64-bit support on Mac OS 10.6, we decided to use FFmpeg to decode movies in Vuo (just like Kineme VideoTools). After the Vuo 1.0.0 release, we’re planning to drop Mac OS 10.6 support, at which point we’ll be able to add AVFoundation support for movie decoding, too.)