Cannot Activate Pro Sites Plugin

I cannot activate Pro Sites. It is returning an error.

Message is:

"Plugin could not be activated because it triggered a fatal error.

Warning: require_once(/home/taxtutor/public_html/wp-content/plugins/pro-sites/pro-sites-files/modules/.php): failed to open stream: No such file or directory in /home/taxtutor/public_html/wp-content/plugins/pro-sites/pro-sites-files/plugins-loader.php on line 38

Fatal error: require_once(): Failed opening required '/home/taxtutor/public_html/wp-content/plugins/pro-sites/pro-sites-files/modules/.php' (include_path='.:disappointed:usr/lib/php:disappointed:usr/local/lib/php') in /home/taxtutor/public_html/wp-content/plugins/pro-sites/pro-sites-files/plugins-loader.php on line 38

I have reinstalled Wordpress Core
I have reinstalled the blog 2 theme
I have removed and reinstalled Pro Sites
I have deactivated all plugins and reinstalled Pro sites.

I cannot identify any code snippets that affect the plugin (I cannot find the appropriate thread) that were not removed by deleting the entire plugin directory.

Could a snippet have altered the database in some way?

Please, please, help.
Kirk