We've been hearing that MediaLab is having problems playing movies on some Vista systems. We are looking into this now but a quick fix would be to embed the movie in an HTML file and then present it as an HTML item (or optionally present that HTML as a background). Note that this approcah can be taken in any situation where MediaLab is having trouble playing your video(s).
If you paste the following into a text file, replace "test.mpg" with the name of your video, and then save the file as myvideo.htm (or whatever) you should be able to use it to show your video. This ought to work for wmv and mpg files. Not sure, off hand, if it would work for quicktime (.mov) files. Note that you could leave off the width and height info you just want it to play in it's normal size.
Code:
<!-- saved from url=(0013)about:internet -->
<body bgcolor="#ccccff">
<object type="video/x-ms-wmv" width="320" height="240">
<param name="src" value="test.mpg"/>
<param name="enableContextMenu" VALUE="0"/>
<param name="windowlessvideo" value="1"/>
<param name="showcontrols" value="0"/>
<param name="autostart" value="1"/></object>
</body>
Also note that this method can be used to show a video that would allow subjects to pause and restart the video via the showcontrols parameter. Just change that value to "1".