Vuejs with vue-cli: Error when running "npm run dev"

My environment:

• Centos7 on VirtualBox (true OS : Windows 7)
• Node version: 6.10.3
• Npm version : 3.10.10
• I'm behind a corporate proxy

I installed vue-cli, like this:

sudo npm install -g vue-cli

Then I init a new project "vuetest", like this:

vue init webpack-simple vuetest

But now, I get an error when running "npm run dev". The error:

> vuetest@1.0.0 dev /var/www/html/vuetest
> cross-env NODE_ENV=development webpack-dev-server --open --hot

events.js:160
      throw er; // Unhandled 'error' event
      ^

Error: spawn webpack-dev-server ENOENT
    at exports._errnoException (util.js:1018:11)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:193:32)
    at onErrorNT (internal/child_process.js:367:16)
    at _combinedTickCallback (internal/process/next_tick.js:80:11)
    at process._tickCallback (internal/process/next_tick.js:104:9)
    at Module.runMain (module.js:606:11)
    at run (bootstrap_node.js:390:7)
    at startup (bootstrap_node.js:150:9)
    at bootstrap_node.js:505:3

npm ERR! Linux 3.10.0-514.el7.x86_64
npm ERR! argv "/usr/bin/node" "/usr/bin/npm" "run" "dev"
npm ERR! node v6.10.3
npm ERR! npm  v3.10.10
npm ERR! code ELIFECYCLE
npm ERR! vuetest@1.0.0 dev: `cross-env NODE_ENV=development webpack-dev-server --open --hot`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the vuetest@1.0.0 dev script 'cross-env NODE_ENV=development webpack-dev-server --open --hot'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the vuetest 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 webpack-dev-server --open --hot
npm ERR! You can get information on how to open an issue for this project with:
npm ERR!     npm bugs vuetest
npm ERR! Or if that isn't available, you can get their info via:
npm ERR!     npm owner ls vuetest
npm ERR! There is likely additional logging output above.
npm WARN Local package.json exists, but node_modules missing, did you mean to install?

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

Does anyone know how to fix it please?

via Baptiste