Fatal Error on activation with 4.5 upgrade. On line 30 of playlist-controller.php, you assume wp-config.php exists at the site root. Mine does not; for security reasons, it is placed one level above the site root.
Fatal error: require_once() [function.require]: Failed opening required '/wp-config.php' (include_path='.:/usr/lib/php5') in /wp-content/plugins/proplayer/playlist-controller.php on line 30
NOTE: Since Version 2.6, wp-config.php can be moved to the directory directly above the WordPress application directory.