npm ERR! Refusing to delete: /usr/local/bin/grunt not in /usr/local/lib/node_modules/grunt-cli
File exists: /usr/local/bin/grunt
Move it away, and try again.

npm ERR! System Linux 3.16.0-4-amd64
npm ERR! command "/usr/bin/nodejs" "/usr/bin/npm" "install" "-g" "grunt" "grunt-cli" "bower"
npm ERR! cwd /usr/src/freeswitch-1.6.12/html5/verto/verto_communicator
npm ERR! node -v v0.10.29
npm ERR! npm -v 1.4.21
npm ERR! path /usr/local/bin/grunt
npm ERR! code EEXIST
/usr/local/bin/grunt -> /usr/local/lib/node_modules/grunt/bin/grunt
/usr/local/bin/bower -> /usr/local/lib/node_modules/bower/bin/bower
npm ERR!
npm ERR! Additional logging details can be found in:
npm ERR!     /usr/src/freeswitch-1.6.12/html5/verto/verto_communicator/npm-debug.log
npm ERR! not ok code 0

module.js:340
    throw err;
          ^
Error: Cannot find module 'grunt-cli/bin/grunt'
    at Function.Module._resolveFilename (module.js:338:15)
    at Function.Module._load (module.js:280:25)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at Object.<anonymous> (/usr/local/lib/node_modules/grunt/bin/grunt:3:1)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Function.Module.runMain (module.js:497:10)