impossible to use any node package added

[radjivF]

Hi,

I have installed

material-ui react-toolbox

And I cannot use it them in the Main component any idea?

my code

require('styles/App.css');

import React from 'react';
import { render } from 'react-dom';
import { Button } from 'react-toolbox/lib/button';

let logoImage = require('../images/origin.jpg');

class AppComponent extends React.Component {
  render() {
    return (

      <Button label="Hello World!" />

    );
  }
}

AppComponent.defaultProps = {
};

export default AppComponent;

error

warning.js?8a56:33 Warning: React.createElement: type is invalid -- expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in. Check the render method of `AppComponent`. in AppComponent printWarning @ warning.js?8a56:33 warning @ warning.js?8a56:57 createElement @ ReactElementValidator.js?a599:190 render @ Main.js?7cd4:14 (anonymous) @ makeAssimilatePrototype.js?c7d8:15 (anonymous) @ ReactCompositeComponent.js?d2b3:793 measureLifeCyclePerf @ ReactCompositeComponent.js?d2b3:73 _renderValidatedComponentWithoutOwnerOrContext @ ReactCompositeComponent.js?d2b3:792 _renderValidatedComponent @ ReactCompositeComponent.js?d2b3:819 performInitialMount @ ReactCompositeComponent.js?d2b3:359 mountComponent @ ReactCompositeComponent.js?d2b3:255 mountComponent @ ReactReconciler.js?399b:43 performInitialMount @ ReactCompositeComponent.js?d2b3:368 mountComponent @ ReactCompositeComponent.js?d2b3:255 mountComponent @ ReactReconciler.js?399b:43 mountComponentIntoNode @ ReactMount.js?26a9:102 perform @ Transaction.js?f15f:141 batchedMountComponentIntoNode @ ReactMount.js?26a9:124 perform @ Transaction.js?f15f:141 batchedUpdates @ ReactDefaultBatchingStrategy.js?e9be:60 batchedUpdates @ ReactUpdates.js?8e6b:95 _renderNewRootComponent @ ReactMount.js?26a9:317 _renderSubtreeIntoContainer @ ReactMount.js?26a9:399 render @ ReactMount.js?26a9:420 (anonymous) @ index.js?9552:7 (anonymous) @ VM19946:24 (anonymous) @ VM19946:25 (anonymous) @ app.js:1051 __webpack_require__ @ app.js:556 fn @ app.js:87 (anonymous) @ app.js:588 __webpack_require__ @ app.js:556 (anonymous) @ app.js:579 (anonymous) @ app.js:582 invariant.js?4599:42 Uncaught Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in. Check the render method of `AppComponent`. at invariant (eval at <anonymous> (app.js:1177), <anonymous>:42:15) at ReactCompositeComponentWrapper.instantiateReactComponent [as _instantiateReactComponent] (eval at <anonymous> (app.js:1585), <anonymous>:72:55) at ReactCompositeComponentWrapper.performInitialMount (eval at <anonymous> (app.js:1591), <anonymous>:364:22) at ReactCompositeComponentWrapper.mountComponent (eval at <anonymous> (app.js:1591), <anonymous>:255:21) at Object.mountComponent (eval at <anonymous> (app.js:1537), <anonymous>:43:35) at ReactCompositeComponentWrapper.performInitialMount (eval at <anonymous> (app.js:1591), <anonymous>:368:34) at ReactCompositeComponentWrapper.mountComponent (eval at <anonymous> (app.js:1591), <anonymous>:255:21) at Object.mountComponent (eval at <anonymous> (app.js:1537), <anonymous>:43:35) at mountComponentIntoNode (eval at <anonymous> (app.js:1117), <anonymous>:102:32) at ReactReconcileTransaction.perform (eval at <anonymous> (app.js:1579), <anonymous>:141:20)

Thanks