Error gulpifle

gulpfile.js

// error
var gulp = require('gulp');
var jade = require('gulp-jade');
var stylus = require('gulp-stylus');

var EXPRESS_PORT = 4000;
var EXPRESS_ROOT = __dirname;
var LIVERELOAD_PORT = 35729;
var lr;

gulp.task('jade', function () {

  gulp.src('./*.jade')
    .pipe(jade())
    .pipe(gulp.dest('./public'));

});

gulp.task('stylus', function () {

  gulp.src('./*.styl')
    .pipe(stylus())
    .pipe(gulp.dest('./public'));

});

gulp.task('express', function () {

  var express = require('express');
  var app = express();
  app.use(require('connect-livereload')());
  app.use(express.static(EXPRESS_ROOT));
  app.listen(EXPRESS_PORT);

});

gulp.task('livereload', function () {

  lr = require('tiny-lr')();
  lr.listen(LIVERELOAD_PORT);

});

gulp.task('notify-lr', function () {

  gulp.src(event.path, {read: false})
      .pipe(require('gulp-livereload')(lr));

});

gulp.task('watch', function () {

  gulp.watch('*.jade', ['jade']);
  gulp.watch(['public/*.html'], notifyLivereload);

  gulp.watch('*.styl', ['stylus']);
  gulp.watch(['public/*.css'], notifyLivereload);

});

gulp.task('default', [ 'express', 'livereload', 'jade', 'stylus', 'notify-lr', 'watch' ]);