Thanks you for sharing this script! Just a couple of days ago I needed to create a thumbnail preview for my video torrent. Did with the help of this tutorial - http://bytesland.com/view/How-to-make-a-thumbnail-preview-wmv . It did not work for me the first time I tried it, you my need to adjust your output functions.To correct this problem just play the video you want to thumbnail with
media player classic, click on view in the top left corner, then scroll down to options, inside options click on output and adjust the video settings to "default". Hope this will also be helpful for someone! My regards!