Are you using any caching plugins with your site like w3 total cache or wp super cacher? This problem may occur because all of your pages are already cached in your browser.
Also, where do you want the plugin to be, in the right side or in the left side of the page?
I signed up to your site and to me, everything seems to be working. The menu is in the right side when logged in and logged out. Here is what it looks like to me: