Can't install the pop up plugin

Hi,
I'm getting an error massege when i'm installing the plugin:
Fatal error: Cannot redeclare set_popover_url() (previously declared in /home/a13dotco/public_html/networklearningformula.co.il/wp-content/plugins/wordpress-popup/popoverincludes/includes/functions.php:3) in /home/a13dotco/public_html/networklearningformula.co.il/wp-content/plugins/popover/popoverincludes/includes/functions.php on line 15

how can i install the plugin?