title: Errors with"npm run dev" command on fresh Laravel 5.4
body: <p>I've been struggling with this for 5 hours now. Here is the error I get when i try to run "npm run dev" on a fresh Laravel install</p>
  
  <pre><code>&gt; @ dev /var/www/html/capsule
  &gt; cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js
  
  events.js:160
        throw er; // Unhandled 'error' event
        ^
  
  Error: spawn node_modules/webpack/bin/webpack.js ENOENT
      at exports._errnoException (util.js:1022:11)
      at Process.ChildProcess._handle.onexit (internal/child_process.js:193:32)
      at onErrorNT (internal/child_process.js:359:16)
      at _combinedTickCallback (internal/process/next_tick.js:74:11)
      at process._tickCallback (internal/process/next_tick.js:98:9)
      at Module.runMain (module.js:606:11)
      at run (bootstrap_node.js:394:7)
      at startup (bootstrap_node.js:149:9)
      at bootstrap_node.js:509:3
  
  npm ERR! Linux 3.16.0-4-amd64
  npm ERR! argv "/usr/bin/nodejs" "/usr/bin/npm" "run" "dev"
  npm ERR! node v6.9.4
  npm ERR! npm  v2.15.11
  npm ERR! code ELIFECYCLE
  npm ERR! @ dev: `cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js`
  npm ERR! Exit status 1
  npm ERR!
  npm ERR! Failed at the @ dev script 'cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js'.
  npm ERR! This is most likely a problem with the  package,
  npm ERR! not with npm itself.
  npm ERR! Tell the author that this fails on your system:
  npm ERR!     cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js
  npm ERR! You can get information on how to open an issue for this project with:
  npm ERR!     npm bugs
  npm ERR! Or if that isn't available, you can get their info via:
  npm ERR!
  npm ERR!     npm owner ls
  npm ERR! There is likely additional logging output above.
  
  npm ERR! Please include the following file with any support request:
  npm ERR!     /var/www/html/capsule/npm-debug.log
  </code></pre>
  
  <p>Here is my package.json file : </p>
  
  <pre><code>{
    "private": true,
    "scripts": {
      "dev": "cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js",
      "watch": "cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --watch --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js",
      "watch-poll": "cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --watch --watch-poll --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js",
      "hot": "cross-env NODE_ENV=development node_modules/webpack-dev-server/bin/webpack-dev-server.js --inline --hot --config=node_modules/laravel-mix/setup/webpack.config.js",
      "production": "cross-env NODE_ENV=production node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js"
    },
    "devDependencies": {
      "axios": "^0.15.3",
      "bootstrap-sass": "^3.3.7",
      "cross-env": "^3.2.3",
      "jquery": "^3.1.1",
      "laravel-mix": "0.*",
      "lodash": "^4.17.4",
      "vue": "^2.1.10"
    }
  }
  </code></pre>
  
  <p>As you can see I have recent versions of npm and node.</p>
  
  <p>I've been looking for similar issues, tried to re-install and re-build with npm several times, nothing seems to work.</p>
  
  <p>Thanks</p>