I've tried using this plugin in a WP 3.9 installation that has a number of images with incorrect meta data, but I get these errors when I try to run it:
[19-Apr-2014 16:12:05 UTC] PHP Warning: session_start(): Cannot send session cookie - headers already sent in /home/username/public_html/wp-content/plugins/fix-my-posts/plugin.php on line 48
[19-Apr-2014 16:12:05 UTC] PHP Warning: session_start(): Cannot send session cache limiter - headers already sent in /home/username/public_html/wp-content/plugins/fix-my-posts/plugin.php on line 48