Activating Defender 1.4 giving Fatal Error

Activating Defender 1.4 is giving the following Error:
Fatal error: Class 'WD_Module_Manager' not found in /{path_to_site}/wp-content/plugins/wp-defender/wp-defender.php on line 211

Then I tried to manually upload Defender files through FTP. Now activating this plugin gives the following Fatal Error:
Fatal error: Class 'WD_Utils' not found in /{path_to_site}/wp-content/plugins/wp-defender/wp-defender.php on line 370

Weird thing is, "wp-defender.php" doesn't have 370 lines of code. What could be causing this?