I get a "Warning: Cannot assign an empty string to a string offset" when installing the theme?

If you see the following warning after importing the demo content:

Warning: Cannot assign an empty string to a string offset in /.../wp-includes/class.wp-scripts.php on line 454

This is being caused by the rtMedia plugin. In your admin panel, click rtMedia tab and save the page. This will remove the warning from your site.