Umm, you’ll have to trouble shoot it with them. My plugin is “free” but the link you provide is to a “pay for download” plugin – which depends on another pay plugin Post Indexer, which I figure has a good chance of being compatible with their “pay to download” Multisite Privacy plugin.
Any call to the database looking for posts in a core WP function checks against the readability or blog_public option of “1” or “less than or not equal to 1”. But sometimes i’ve seen functions look only for the blog_public option to be “0”. Which wouldn’t work with this plugin.
SO, I offer you this: try wpmudev’s Multisite Privacy plugin. I wager my plugin and theirs change the value of blog_public to the same values “1,0,-1,-2,-3,-4”. If their privacy plugin works, use it. Not really certain what features differ in each. Or what features you are expecting to work with your global feeds.
Other than that, you haven’t offered me much to go on by saying the plugin simply “doesn’t work”.
