WP-Gravatar display name

Hi All,

Got a really niggly problem. I set up a website that uses WP-Gravatar plugin to manage my gravatars, it also manages my authors credit at the end of the post. The problem is some goe to a 404page when you click on ‘more from this author’ rather than the author archive. On investigation, I discovered that it only happened to users who have a display name different from their login name. I am at loss at how to rectify the problem and would appreciate any help. The links below show the one the works well:
http://pridenigeria.com/beauty-style/that-office-look/

and one that doesn’t work:
http://pridenigeria.com/spotlight/wole-oguntokun/

Thanks in advance…