Module interpreted as global module format, but called System.register.

[dara76]

This is part of a simplified test example that can be found at https://github.com/dara76/node-serve-jspm-test

I have the following in my index.html

 <script src="jspm_packages/system.js"></script>
 <script src="config.js"></script>
 <script>
      System.trace = true;
      System.import('./app/main');
  </script>

where main.js is

console.log('main.js');                                                                  
import React from 'react';  

I get the following error

Uncaught (in promise) Error: (SystemJS) Module http://localhost:3000/app/main.js interpreted as global module format, but called System.register.

If I remove the import React from 'react' statement from main.js there is no error and the console.log executes.

How can I avoid getting the above error?