title: Webapp using react-bootstrap loads ok the 1st time then: Uncaught TypeError: Super expression must either be null or a function
body: <p>Hi I'm having a problem with the app I'm building. when i run webpack the app shows in screen and works perfect. But as soon as i make a change to any component and the servers loads the new data i got the console error:</p>
  
  <pre><code>Uncaught TypeError: Super expression must either be null or a function, not undefined
  at Function.exports.default (bundle.js:401)
  at bundle.js:17796
  at Object.&lt;anonymous&gt; (bundle.js:17873)
  at __webpack_require__ (bundle.js:20)
  at Object.&lt;anonymous&gt; (bundle.js:39700)
  at __webpack_require__ (bundle.js:20)
  at Object.&lt;anonymous&gt; (bundle.js:39400)
  at __webpack_require__ (bundle.js:20)
  at Object.defineProperty.value (bundle.js:39324)
  at __webpack_require__ (bundle.js:20)
  </code></pre>
  
  <p>i have to remove and add react-bootstrap again to make it work. Happens on chrome and safari. Any help would be appreciated. Thanks.</p>
  
  <pre><code>"dependencies": {
      "axios": "^0.16.2",
      "babel-cli": "6.24.1",
      "babel-core": "6.25.0",
      "babel-loader": "7.1.1",
      "babel-plugin-transform-class-properties": "6.24.1",
      "babel-preset-env": "1.5.2",
      "babel-preset-react": "6.24.1",
      "bootstrap": "3.3.7",
      "css-loader": "^0.28.7",
      "express": "^4.16.1",
      "extract-text-webpack-plugin": "^3.0.1",
      "file-loader": "^1.1.5",
      "live-server": "^1.2.0",
      "node-sass": "^4.5.3",
      "normalize.css": "^7.0.0",
      "react": "15.6.1",
      "react-bootstrap": "^0.31.3",
      "react-dom": "15.6.1",
      "sass-loader": "^6.0.6",
      "style-loader": "^0.18.2",
      "url-loader": "^0.6.2",
      "webpack": "3.1.0",
      "webpack-dev-server": "2.5.51"
    }
  </code></pre>