Gulp Uglify Error:

Me parece instalação problemática, já tentou reinstalar o uglify?

Vou reinstalar.

reinstalei mas continua com o mesmo erro.

O mesmo erro? Você pode postar aqui o gulpfile.js pra gente ver o que pode ser?

Segue meu gulpfile.js:

var gulp          = require('gulp');
var imagemin      = require('gulp-imagemin');
var clean         = require('gulp-clean');
var concat        = require('gulp-concat');
var uglify        = require('gulp-uglify');
var usemin        = require('gulp-usemin');
var cssmin        = require('gulp-cssmin');
var browserSync   = require('browser-sync');
var jshint        = require('gulp-jshint');
var jshintStylish = require('jshint-stylish');
var csslint       = require('gulp-csslint');
var autoPrefixer  = require('gulp-autoprefixer');
var less          = require('gulp-less');

gulp.task('default', ['copy'], function(){
    gulp.start('build-img', 'usemin');
});

gulp.task('copy', ['clean'], function(){
    return gulp.src('site/**/*')
        .pipe(gulp.dest('dist'));
});

gulp.task('clean', function(){
    return gulp.src('dist')
        .pipe(clean());
});

gulp.task('build-img', function(){
    gulp.src('dist/images/**/*')
        .pipe(imagemin())
        .pipe(gulp.dest('dist/images'));
});

gulp.task('usemin', function(){
    gulp.src('dist/**/*.html')
        .pipe(usemin({
            'js': [uglify],
            'css': [autoPrefixer, cssmin]
        }))['transform-runtime']}))
        .pipe(gulp.dest('dist'));
});

gulp.task('server', function(){
    browserSync.init({
        server: {
            baseDir: 'src'
        }
    });

    gulp.watch('site/js/*.js').on('change', function(event){
        gulp.src(event.path)
            .pipe(jshint())
            .pipe(jshint.reporter(jshintStylish));
    });

    gulp.watch('site/css/*.css').on('change', function(event){
        gulp.src(event.path)
            .pipe(csslint())
            .pipe(csslint.reporter());
    });

    gulp.watch('site/**/*').on('change', browserSync.reload);
});

Erro que esta dando ao executar o npm run gulp:

stream.js:94
      throw er; // Unhandled stream error in pipe.
            ^
Error
    at new JS_Parse_Error (/var/www/empresa/node_modules/uglify-js/lib/parse.js:196:18)
    at js_error (/var/www/empresa/node_modules/uglify-js/lib/parse.js:204:11)
    at croak (/var/www/empresa/node_modules/uglify-js/lib/parse.js:684:41)
    at token_error (/var/www/empresa/node_modules/uglify-js/lib/parse.js:688:9)
    at expect_token (/var/www/empresa/node_modules/uglify-js/lib/parse.js:701:9)
    at expect (/var/www/empresa/node_modules/uglify-js/lib/parse.js:704:36)
    at maybe_conditional (/var/www/empresa/node_modules/uglify-js/lib/parse.js:1407:13)
    at maybe_assign (/var/www/empresa/node_modules/uglify-js/lib/parse.js:1427:20)
    at expression (/var/www/empresa/node_modules/uglify-js/lib/parse.js:1446:20)
    at maybe_conditional (/var/www/empresa/node_modules/uglify-js/lib/parse.js:1412:31)
    at maybe_assign (/var/www/empresa/node_modules/uglify-js/lib/parse.js:1427:20)
    at expression (/var/www/empresa/node_modules/uglify-js/lib/parse.js:1446:20)

npm ERR! Linux 3.13.0-103-generic
npm ERR! argv "/home/gustavo/.nvm/versions/node/v0.12.17/bin/node" "/home/gustavo/.nvm/versions/node/v0.12.17/bin/npm" "run" "gulp"
npm ERR! node v0.12.17
npm ERR! npm  v2.15.1
npm ERR! code ELIFECYCLE
npm ERR! projeto@1.0.0 gulp: `gulp`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the projeto@1.0.0 gulp script 'gulp'.
npm ERR! This is most likely a problem with the projeto package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     gulp
npm ERR! You can get information on how to open an issue for this project with:
npm ERR!     npm bugs projeto
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! 
npm ERR!     npm owner ls projeto
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR!     /var/www/empresa/npm-debug.log

Gustavo,

Tente chamar o uglify, autoprefixer e cssmin como função, dessa maneira:

gulp.task('usemin', function(){
    gulp.src('dist/**/*.html')
        .pipe(usemin({
            'js': [uglify()],
            'css': [autoPrefixer(), cssmin()]
        }))['transform-runtime']}))
        .pipe(gulp.dest('dist'));
});

Abs!