The root route must render a single element

[code-artisan]

Hi there, I tried copy the source code: https://github.com/reactjs/react-router/tree/master/examples/auth-with-shared-root to my project, after it, I configured wepack and start dev server. I got an error:
The root route must render a single element.

[code-artisan]

{
  // ...
  "dependencies": {
    "react": "^0.14.0",
    "react-dom": "^0.14.0",
    "react-router": "1.0.1"
  },
  "devDependencies": {
    "babel-core": "^6.5.2",
    "babel-loader": "^6.2.3",
    "babel-preset-es2015": "^6.5.0",
    "babel-preset-react": "^6.5.0",
    "webpack": "^1.12.13",
    "webpack-dev-server": "^1.14.1"
  }
}

[knowbody]

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