var ITTrackKindFile = 1;

var iTunesApp = WScript.CreateObject("iTunes.Application");
var mainLibrary = iTunesApp.LibraryPlaylist;
var tracks = mainLibrary.Tracks;

for(var i = 0; i < tracks.Count; i = i + 1) {
    var currTrack = tracks.Item(i+1);
    if (currTrack.Kind != ITTrackKindFile)
    continue;
    currTrack.AlbumRating = 1;
}