Plugin Activate

Hello,

if I Try to Activate the Plugin in WordPress we get this Error Message.

Fatal error: Uncaught Error: Call to a member function add_cap() on null in C:\inetpub\wwwroot\wp-content\plugins\js-support-ticket\includes\activation.php:21 Stack trace: #0 C:\inetpub\wwwroot\wp-content\plugins\js-support-ticket\includes\activation.php(13): JSSTactivation::addCapabilites() #1 C:\inetpub\wwwroot\wp-content\plugins\js-support-ticket\js-support-ticket.php(125): JSSTactivation::jssupportticket_activate() #2 C:\inetpub\wwwroot\wp-includes\class-wp-hook.php(287): jssupportticket->jssupportticket_activate(”) #3 C:\inetpub\wwwroot\wp-includes\class-wp-hook.php(311): WP_Hook->apply_filters(”, Array) #4 C:\inetpub\wwwroot\wp-includes\plugin.php(478): WP_Hook->do_action(Array) #5 C:\inetpub\wwwroot\wp-admin\plugins.php(193): do_action(‘activate_js-sup…’) #6 {main} thrown in C:\inetpub\wwwroot\wp-content\plugins\js-support-ticket\includes\activation.php on line 21

Can you Help use ?

Thanks