Thank you.
I took a screenshot of the comment form on your blog with Google Chrome, Mozilla Firefox, and Internet Explorer (see links below). As you can see, the password shows up properly on the comment form, so you have the plugin installed and working correctly.
https://www.toddlahman.com/images/2011/chrome-1.jpg
https://www.toddlahman.com/images/2011/firefox-1.jpg
https://www.toddlahman.com/images/2011/internet-explorer-1.jpg
If you are not able to see the password field in your web browser, empty the cache, then view the page again.
The plugin renders the password field exactly the same way WordPress renders the name, email, and website fields on the form to insure there will be no problem with visibility.