The problem is that the plugin is trying to echo data (re-sending the headers) after they have been sent.
Here is line 178 of the plugin echo "<div id=\"comment-".$str."\"><a href="#".$str."">noted on #".$imgIDNow."</a></div>";
I would need more information on which page the plugin was failing on. What the plugin does, what you are trying to do to be able to help you further.