While you are not able to execute the "hello.php" file into the sub-directory, you have to check your hosting permission and configuration.
This is not related to Joomla or JMS.
The content of the index.php files is correct.
It will only be executed when you will have found the reason of the permission error in the sub-directory.
This is an administrative work that is not related to JMS or Joomla as you can not event execute the "hello.php" file.
Perhaps you have specific parameters in you hosting server (perhaps apache) that does not allow execute files in the /multisites directory.
For you information, if you want that we configure your server for you, this is also possible with billable support that you can order at
www.jms2win.com/download?page=shop.produ...35&category_id=1