I get an error on npm start

[Jonatan del Valle]

This is the npm-debug.log

0 info it worked if it ends with ok
1 verbose cli [ '/usr/local/bin/node', '/usr/local/bin/npm', 'start' ]
2 info using npm@3.5.2
3 info using node@v4.2.3
4 verbose run-script [ 'prestart', 'start', 'poststart' ]
5 info lifecycle yarsk@1.0.0prestart: yarsk@1.0.0
6 silly lifecycle yarsk@1.0.0prestart: no script for prestart, continuing
7 info lifecycle yarsk@1.0.0start: yarsk@1.0.0
8 verbose lifecycle yarsk@1.0.0start: unsafe-perm in lifecycle true
9 verbose lifecycle yarsk@1.0.0start: PATH: /usr/local/lib/node_modules/npm/bin/node-gyp-bin:/Users/jonatan/projects/reactStarter/node_modules/.bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin
10 verbose lifecycle yarsk@1.0.0start: CWD: /Users/jonatan/projects/reactStarter
11 silly lifecycle yarsk@1.0.0start: Args: [ '-c',
11 silly lifecycle 'webpack-dev-server --config conf/webpack.config.js --hot --progress --colors --content-base ./build' ]
12 silly lifecycle yarsk@1.0.0start: Returned: code: 1 signal: null
13 info lifecycle yarsk@1.0.0~start: Failed to exec start script
14 verbose stack Error: yarsk@1.0.0 start: webpack-dev-server --config conf/webpack.config.js --hot --progress --colors --content-base ./build
14 verbose stack Exit status 1
14 verbose stack at EventEmitter. (/usr/local/lib/node_modules/npm/lib/utils/lifecycle.js:232:16)
14 verbose stack at emitTwo (events.js:87:13)
14 verbose stack at EventEmitter.emit (events.js:172:7)
14 verbose stack at ChildProcess. (/usr/local/lib/node_modules/npm/lib/utils/spawn.js:24:14)
14 verbose stack at emitTwo (events.js:87:13)
14 verbose stack at ChildProcess.emit (events.js:172:7)
14 verbose stack at maybeClose (internal/child_process.js:818:16)
14 verbose stack at Process.ChildProcess._handle.onexit (internal/child_process.js:211:5)
15 verbose pkgid yarsk@1.0.0
16 verbose cwd /Users/jonatan/projects/reactStarter
17 error Darwin 15.3.0
18 error argv "/usr/local/bin/node" "/usr/local/bin/npm" "start"
19 error node v4.2.3
20 error npm v3.5.2
21 error code ELIFECYCLE
22 error yarsk@1.0.0 start: webpack-dev-server --config conf/webpack.config.js --hot --progress --colors --content-base ./build
22 error Exit status 1
23 error Failed at the yarsk@1.0.0 start script 'webpack-dev-server --config conf/webpack.config.js --hot --progress --colors --content-base ./build'.
23 error Make sure you have the latest version of node.js and npm installed.
23 error If you do, this is most likely a problem with the yarsk package,
23 error not with npm itself.
23 error Tell the author that this fails on your system:
23 error webpack-dev-server --config conf/webpack.config.js --hot --progress --colors --content-base ./build
23 error You can get information on how to open an issue for this project with:
23 error npm bugs yarsk
23 error Or if that isn't available, you can get their info via:
23 error npm owner ls yarsk
23 error There is likely additional logging output above.
24 verbose exit [ 1, true ]