Cannot find a module

I installed grunt-cli, then “npm install”, for get some error with the module ‘lru-cache’ !

sudo npm install -g grunt-cli
npm install

the print:

roots-master git:(master) ✗ grunt help
Loading "jshint.js" tasks...ERROR
>> Error: Cannot find module 'lru-cache'
Warning: Task "help" not found. Use --force to continue.

Aborted due to warnings.

Execution Time (2014-07-19 16:20:07 UTC)
loading tasks  4ms  ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 40%
Total 10ms

➜  roots-master git:(master) ✗ 

Do I have to start each module ?

npm install <module> --save-dev

Can you try deleting your node_modules/ directory and run npm install again, then try grunt one more time. Paste any output.

I did, but it stay blocked, for ever:

npm http 304
npm http 304
npm http GET
npm http 304