I modified my “comments.html” like this:
{$comment->comment_author_email|gravatar:”":”32″:”":”"}

the above line should be put before:
{comment_author_link}

and don’t forget to register for an avatar using en.gravatar.com.

By the way, I can’t post anything in you comment, seems like there’s error with you code… I think you delete the anti-spam image, so I can’t see the image for verification.
Hope that’ll help.