Delete your Java 1.3 & update to the latest Java http://www.java.com/en/download/windows_automatic.jsp (that's probably the best to to force the interntional version to use the update version!)

Also although you can preview video from LW's dwnld's. May I highly recommend that you normally only play video outside of LW; ie: if it's already dwnlded, then open it using your default video player & not using LW as a go-between. This is obviously causing some issues on your comp. Within you incomplete folder you'll also find Preview files which are created everytime you preview a file. May I suggest you delete these (only the preview files.) If you have previewed many video files, then you may have many of these which are taking up valuable space! I've heard of people running out of hard disk space because they hadn't cleaned out their video preview files.