You're going to the wrong place.
Script menu's are placed under the script icon in your contact list or in any chat window. When you click it, a menu pops up with all active scripts who have a script menu available, including Countdown Live. In that menu, you can find the Preferences menu.
PS: I'm the developer of Countdown Live, so if you have any other questions related to this particular script, feel free to PM me. I always like comments and suggestions about my scripts, so I can improve them.