IP Geo Block: Plugin could not be activated because it triggered a fatal error

Here is the error message after attempting to activate:
Fatal error: Uncaught Error: Call to a member function dirlist() on null in /var/www/html/wp-admin/includes/file.php:1663 Stack trace: #0 /var/www/html/wp-content/plugins/ip-geo-block/classes/class-ip-geo-block-opts.php(482): copy_dir('/var/www/html/w...', '/ip-geo-api/') #1 /var/www/html/wp-content/plugins/ip-geo-block/classes/class-ip-geo-block-opts.php(455): IP_Geo_Block_Opts::install_api(Array) #2 /var/www/html/wp-content/plugins/ip-geo-block/classes/class-ip-geo-block-actv.php(36): IP_Geo_Block_Opts::upgrade() #3 /var/www/html/wp-content/plugins/ip-geo-block/classes/class-ip-geo-block-actv.php(54): IP_Geo_Block_Activate::activate_blog() #4 /var/www/html/wp-content/plugins/ip-geo-block/ip-geo-block.php(56): IP_Geo_Block_Activate::activate('') #5 /var/www/html/wp-includes/class-wp-hook.php(286): ip_geo_block_activate('') #6 /var/www/html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters('', Array) #7 /var/www/html/wp-includes/plugin.php(465): WP_Hook->do_action(Array) #8 /var/www/html/wp-admin/plugins.php(177) in /var/www/html/wp-admin/includes/file.php on line 1663