setup problem

[mesutgok]

Hi,

how do i fix ?

error code :

> [email protected] start /Projects/node-web-crawler
> node app

module.js:341
    throw err;
    ^

Error: Cannot find module 'mongodb/lib/mongodb/connection/read_preference'
    at Function.Module._resolveFilename (module.js:339:15)
    at Function.Module._load (module.js:290:25)
    at Module.require (module.js:367:17)
    at require (internal/module.js:16:19)
    at Object.<anonymous> (/Projects/node-web-crawler/node_modules/mongoose/lib/utils.js:5:16)
    at Module._compile (module.js:413:34)
    at Object.Module._extensions..js (module.js:422:10)
    at Module.load (module.js:357:32)
    at Function.Module._load (module.js:314:12)
    at Module.require (module.js:367:17)

Good works.