This is very strange. Maybe it will help to try the following steps in order:
1) open a command prompt as administrator. Type "sfc /scannow" to run the System File Check utility. Let us know if Windows reports any problems that it can't fix. Try importing the video clip.
2) If that doesn't work, uninstall PD14 (SmartSound AND Quicktime should prompt you to allow each to be uninstalled. Click Yes). Also uninstall the graphics card driver and reboot when finished.
3) Download and install the latest graphics card driver, then reinstall PD14 (and click Yes to SmartSound and Quicktime. You may need to manually update QT afterwards). See if you can import the video.