npm run build gives out npm ERR! code ELIFECYCLE

I'm very new to Node.js and Electron and wanted to run npm run build. Unfortunately, that only gives me out the error code ELIFECYCLE.

Here is my package.json:

{
    "name": "firstelectronproject",
    "version": "0.1.0",
    "description": "My first Electron project",
    "main": "main.js",
    "scripts": {
        "start": "electron index.js",
        "package": "",
        "build": "electron-packager . FEP"
    },
    "author": "F9lke <florian.thomasgoetzrath.de>",
    "license": "MIT",
    "dependencies": {
        "electron": "^1.6.11"
    },
    "devDependencies": {
        "asar": "^0.13.0",
        "electron-packager": "^8.7.2"
    }
}

Here is the log of my command prompt:

 D:\Eigene Dateien\Desktop\Coding\Desktop Apps\FEP>npm run build

> firstelectronproject@0.1.0 build D:\Eigene Dateien\Desktop\Coding\Desktop Apps\FEP
> electron-packager . FEP

Packaging app for platform win32 x64 using electron v1.6.11
Command failed: npm prune --production
npm WARN invalid config loglevel="notice"
npm WARN firstelectronproject@0.1.0 No repository field.

npm ERR! May not delete: C:\Users\User\AppData\Local\Temp\electron-packager\win32-x64\FEP-win32-x64\resources\app\node_modules\.bin

npm ERR! A complete log of this run can be found in:
npm ERR!     C:\Users\User\AppData\Roaming\npm-cache\_logs\2017-07-21T11_38_37_230Z-debug.log

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! firstelectronproject@0.1.0 build: `electron-packager . FEP`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the firstelectronproject@0.1.0 build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     C:\Users\User\AppData\Roaming\npm-cache\_logs\2017-07-21T11_38_37_293Z-debug.log  

And here is the log output:

0 info it worked if it ends with ok
1 verbose cli [ 'C:\\Program Files\\nodejs\\node.exe',
1 verbose cli   'C:\\Users\\User\\AppData\\Roaming\\npm\\node_modules\\npm\\bin\\npm-cli.js',
1 verbose cli   'run',
1 verbose cli   'build' ]
2 info using npm@5.3.0
3 info using node@v6.11.1
4 verbose run-script [ 'prebuild', 'build', 'postbuild' ]
5 info lifecycle firstelectronproject@0.1.0~prebuild: firstelectronproject@0.1.0
6 info lifecycle firstelectronproject@0.1.0~build: firstelectronproject@0.1.0
7 verbose lifecycle firstelectronproject@0.1.0~build: unsafe-perm in lifecycle true
8 verbose lifecycle firstelectronproject@0.1.0~build: PATH: C:\Users\User\AppData\Roaming\npm\node_modules\npm\bin\node-gyp-bin;D:\Eigene Dateien\Desktop\Coding\Desktop Apps\FEP\node_modules\.bin;C:\Program Files (x86)\Razer Chroma SDK\bin;C:\Program Files\Razer Chroma SDK\bin;C:\Program Files (x86)\Intel\iCLS Client\;C:\Program Files\Intel\iCLS Client\;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;C:\Windows\system32\config\systemprofile\AppData\Local\Microsoft\WindowsApps;C:\Program Files (x86)\Brackets\command;C:\Program Files\nodejs\;C:\Users\User\AppData\Local\Microsoft\WindowsApps;C:\Users\User\AppData\Local\atom\bin;C:\Users\User\AppData\Roaming\npm
9 verbose lifecycle firstelectronproject@0.1.0~build: CWD: D:\Eigene Dateien\Desktop\Coding\Desktop Apps\FEP
10 silly lifecycle firstelectronproject@0.1.0~build: Args: [ '/d /s /c', 'electron-packager . FEP' ]
11 silly lifecycle firstelectronproject@0.1.0~build: Returned: code: 1  signal: null
12 info lifecycle firstelectronproject@0.1.0~build: Failed to exec build script
13 verbose stack Error: firstelectronproject@0.1.0 build: `electron-packager . FEP`
13 verbose stack Exit status 1
13 verbose stack     at EventEmitter.<anonymous> (C:\Users\User\AppData\Roaming\npm\node_modules\npm\lib\utils\lifecycle.js:289:16)
13 verbose stack     at emitTwo (events.js:106:13)
13 verbose stack     at EventEmitter.emit (events.js:191:7)
13 verbose stack     at ChildProcess.<anonymous> (C:\Users\User\AppData\Roaming\npm\node_modules\npm\lib\utils\spawn.js:40:14)
13 verbose stack     at emitTwo (events.js:106:13)
13 verbose stack     at ChildProcess.emit (events.js:191:7)
13 verbose stack     at maybeClose (internal/child_process.js:891:16)
13 verbose stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:226:5)
14 verbose pkgid firstelectronproject@0.1.0
15 verbose cwd D:\Eigene Dateien\Desktop\Coding\Desktop Apps\FEP
16 verbose Windows_NT 10.0.15063
17 verbose argv "C:\\Program Files\\nodejs\\node.exe" "C:\\Users\\User\\AppData\\Roaming\\npm\\node_modules\\npm\\bin\\npm-cli.js" "run" "build"
18 verbose node v6.11.1
19 verbose npm  v5.3.0
20 error code ELIFECYCLE
21 error errno 1
22 error firstelectronproject@0.1.0 build: `electron-packager . FEP`
22 error Exit status 1
23 error Failed at the firstelectronproject@0.1.0 build script.
23 error This is probably not a problem with npm. There is likely additional logging output above.
24 verbose exit [ 1, true ]