Can't find module

I just run the `npm install` and `ng serve`
but when I run the `ng serve`
I get this error;

> Cannot find module 'webpack/lib/dependencies/ContextElementDependency'
> Error: Cannot find module 'webpack/lib/dependencies/ContextElementDependency'
> at Function.Module._resolveFilename (module.js:536:15)
> at Function.Module._load (module.js:466:25)
> at Module.require (module.js:579:17)
> at require (internal/module.js:11:18)
> at Object. (/Volumes/Work/Client/Devxy/pouchdb-angular2/node_modules/@ngtools/webpack/src/plugin.js:8:34)
> at Module._compile (module.js:635:30)
> at Object.Module._extensions..js (module.js:646:10)
> at Module.load (module.js:554:32)
> at tryModuleLoad (module.js:497:12)
> at Function.Module._load (module.js:489:3)

What can I do?
I will be appreciate if anyone help me. :)