This error usually stems from a problem with the installation of Quicktime on your computer. Storyteller uses components of Quicktime to play the movies from the camera.
We suggest that you do the following steps in this order:
1) Uninstall Storyteller
2) Uninstall Quicktime
3) Reinstall Quicktime (http://www.apple.com/quicktime/download/)
4) Reinstall Storyteller (http://contour.com/storyteller)
That should correct the error.