React router throws and error when getting async component

I'm using react, redux and react router amoung others to build and example app.

I'm trying to load asynchronously different parts of my application. I've divided my app in ducks and I'm following this example https://github.com/insin/react-examples/tree/master/code-splitting-redux-reducers

But I'm getting this error:

Uncaught Invariant Violation: The root route must render a single element

When trying to get async component with getComponent method of react router. I'm using: react-router 2.0.1

My routes:

export default function configureRoutes(reducerRegistry) {
  return(
    <Route>
      <Route component={Landing}>
        <Route path='/login' component={Login}/>
        <Route path='/register' component={Register}/>
      </Route>
            <Route path="admin" getComponent={(location, cb) => {
                require.ensure([], require => {
                    cb(null, require('./containers/admin'))
                })
            }}/>
      <Route component={App}>
        <Route  path='/' component={Home} />
      </Route>
    </Route>
)}

My component

class Admin extends Component {
  componentDidMount() {
    this.props.load()  
  }
  render() {
    const { message, isFetching } = this.props
    return (
      <div>
        <p>{message}</p> 
        <p>This module was loaded via chunk </p>
        {loading && <p>Doing some fake loading ...</p>}
      </div>
    )  
  }  
}

Admin.propTypes = {
  message: PropTypes.string.isRequired,
  isFetching: PropTypes.bool.isRequired,
  load: PropTypes.string.isRequired
}

const mapStateToProps = state => state.admin

function mapDispatchToProps(dispatch) {
  return bindActionCreators({ load }, dispatch)
}

export default connect(mapStateToProps, mapDispatchToProps)(Admin)

Does anyone have the same error? any ideas? Anyone have something similar working?

Thanks community!

Update: Added index.js for clarity

import configureRoutes from './routes'
import configureStore from './store/configureStore'
import coreReducers from './modules/core'
import ReducerRegistry from './reducer-registry'

var reducerRegistry = new ReducerRegistry(coreReducers)

// Configure hot module replacement for core reducers
if (process.env.NODE_ENV !== 'production') {
  if (module.hot) {
    module.hot.accept('./modules/core', () => {
      var nextCoreReducers = require('./modules/core')
      reducerRegistry.register(nextCoreReducers)
    })
  }
}

const routes = configureRoutes(reducerRegistry)
const store = configureStore(reducerRegistry)

render(
  <I18nextProvider i18n={i18n}>
    <Provider store={store}>
      <Router history={browserHistory} routes={routes} />
    </Provider>
  </I18nextProvider>,
  document.getElementById('root')
)