I have the same issue. For some reason the plugin adds a full url after the rel= instead of just adding the number for the album. This is how it worked in the first version of the facebook photo fetcher plugin, so I changed all the occurrences url to the number for the album like this: rel="10151222247755185"
You will also have to remove the <!--FBGallery2 10151222247755185 --><!--/FBGallery2--> magic tags as well to prevent it from updating and replacing all your changes with the original code it generated.
Once I realized this worked properly, I went in to the plugin code and found the line causing the issue. It is in the _output_gallery.php file on line 258.
Change this:
$link = '<a rel="' . htmlspecialchars($album->link) . '" class="fbPhoto" href="'.$photo->source . '" title="'.$caption_with_br.' " ><img src="' . $photo->picture . '" alt="" /></a>';
To this:
$link = '<a rel="' . $aid . '" class="fbPhoto" href="'.$photo->source . '" title="'.$caption_with_br.' " ><img src="' . $photo->picture . '" alt="" /></a>';