[Plugin: Simple Facebook Connect] Gravatar / facebook avatar issue

This plugin is awesome. However, I faced some problems when using it.

I am currently using a premium theme called ‘ Aspiration ‘ (demo link: http://preview.ait-themes.com/aspiration/wp1), and the codes inside make the facebook avatar can’t show up, and displays the mysterious man gravatar instead.

I tried many ways to fix the code, but still can’t find out a way to get it done…

Inside the codes, I found that the codes corresponding to the showup of avatar is this one:

protected function getAvatar()
{ return $this->avatar(); }
and

public function avatar($size = null)
{ $id = $this->commentParent if(is_null($size)){
$size = 68; if($id != 0 $size = 39; }
return get_avatar($this->email, $size); }

I am quite sure it should be the theme to be responsible for the problem, as I tried in the default them (Twenty-One), and the facebook avatar is showing up correctly. I’m not good at coding , so I came here and ask for help… Anyways to get it fixed ?