Use an application that can search for text -within- files..
Plonk a copy of the plugins folder on your desktop (Or wherever). If on mac, there's various grep options (i'm not a mac user), and on windows there are free apps such as Text Crawler.
Search the files you've copied for strings of text you need to find..
Example could be:
<h3>Register to Access Now</h3>
Or if that doesn't turn up results then maybe just..
Register to Access Now
Since it's a paid for plugin i can't download it to check for you, but it's simple enough to do (with the right tools).