Digging around the FAQs again on the plugin itself I found this
When I hit “Update & Test” I get an error message saying something about a 404 error
This means that, for some reason, our server is unable to reach your plugin. To test this for yourself, copy the URL from the error messsage into your browser, go to that page, and see what you get. You should see a message telling you that your plugin is working fine. If you get a 404 Page Not Found error, this means one of the following:
I don’t get a 404 error but if I post the url that it says it is having a problem on I was wondering if someone would know why it is saying that this doesn’t exist http://www.bestacidrefluxdiseasediet.com/wp-content/plugins/unique_articles/add_article.php but in fact it does… I can’t figure this out to save my life hah, thanks in advance.