Shared Review Not Working with Adobe Reader

I have seen a couple of other threads but still no solutions. I am having trouble with some of my reviewers being able to access the shared commenting functions on a SharePoint based review.

Here are the steps I've taken:

1. Open PDF in Acrobat Pro X (10.1.1)
2. Send for Shared Review, link to internal SharePoint server
3. All users with Acrobat Pro (versions 9 or 10) can successfully comment and join the shared review
4. Most users with Adobe Reader XI (our current corporate standard) can add comments, but only locally. They are missing the notification to join the shared review, as well as the top bar to look for new comments or publish their comments.
   1. Oddly, there is one user who has successfully joined the review. The only difference I can find on that machine is an IE plugin called "Adobe Acrobat SharePoint OpenDocuments Component" v. 11.0.10.32. I cannot find any route to manually install this on the other machines and verify if that's the key.

Any ideas how to enable our folks with Adobe Reader XI to join the commenting reviews on SharePoint documents?