Can't add Prices

I have created an event. I am unable to add price to the event. The green plus sign is there but when I click it doesn’t do anything. When I view the event it shows this:

Warning: Invalid argument supplied for foreach() in /home/vg004web01/36/60/3006036/web/wordpress/wp-content/plugins/events-planner-pro-1.3.11.5/application/libraries/epl-util.php on line 1390

http://www.ppok.org/event/oklahoma-annual-convention-and-trade-show/

http://wordpress.org/extend/plugins/events-planner/