Getting Fatel error

Hi

I just downloaded the events+ plugin and i installed through ftp and cofigure the plugin.while executing i am getting the one fatal like this

Fatal error: Class 'Booking' not found in /home/xodmedia/www/kew/wp-content/themes/KewGardens/archive-incsub_event.php on line 14

Please help me over this

Thank you.