Fatal error on activation

When activating the plugin it generated this error:

Fatal error: Uncaught Error: Call to undefined method Radio_Player_Widget::instance() in /home/website/public_html/wp-content/plugins/radio-player/includes/class-widget.php:132 Stack trace: #0 /home/website/public_html/wp-content/plugins/radio-player/includes/base.php(76): include_once() #1 /home/website/public_html/wp-content/plugins/radio-player/includes/base.php(27): Radio_Player->includes() #2 /home/website/public_html/wp-content/plugins/radio-player/includes/base.php(181): Radio_Player->__construct() #3 /home/website/public_html/wp-content/plugins/radio-player/includes/base.php(191): Radio_Player::instance() #4 /home/website/public_html/wp-content/plugins/radio-player/includes/base.php(195): radio_player() #5 /home/website/public_html/wp-content/plugins/radio-player/plugin.php(76): include_once('/home/website...') #6 /home/website/public_html/wp-admin/includes/plugin.php(2286): include_once('/home/website...') #7 /home/website/public_html/wp-admin/plugins.php(191): plugin_sandbox_scrape('radio-p in /home/website/public_html/wp-content/plugins/radio-player/includes/class-widget.php on line 132