Error when installing access control

Hi there,

I am getting the following error: “Plugin could not be activated because it triggered a fatal error. Fatal error: Call to undefined function add_wdm_settings_tab() in /home/content/90/7404690/html/wp-content/plugins/wpdm-custom-access-level/wpdm-custom-access-level.php on line 463” when trying to install the advanced access control onto the free version of DM.