In this example, Slider loads a textfile with all the parameters. By default, the textfile must be called the same as the swf file. So in this case, it is called "slider.txt" and you can see it here: slider.txt

You may specify an optional textfile, but the name of the file must then be passed to the swf by flashvars with the datafile parameter. For example:
datafile = mytextfile.txt