Advanced Comment Causing website errors

On my client’s website we use Advanced Comment (PRO) and our query monitor is picking up warning from the plugin. I was hoping you could tell me what is causing these errors and how I can fix them if possible. There are three warning I only get when I access the wordpress backend:
1. fopen(/home/alaska/public_html/wp-content/plugins/wp-advance-comment-pro/index.php): failed to open stream: No such file or directory

wp-includes/functions.php:4833
do_action(‘admin_menu’)
wp-admin/includes/menu.php:149
wpad_update_plugin_notifier_menu()
wp-includes/class-wp-hook.php:286
get_plugin_data()
wp-content/plugins/wp-advance-comment-pros/update-notifier.php:20
get_file_data()
wp-admin/includes/plugin.php:84
fopen()
wp-includes/functions.php:4833

2.fread() expects parameter 1 to be resource, boolean given

wp-includes/functions.php:4836
do_action(‘admin_menu’)
wp-admin/includes/menu.php:149
wpad_update_plugin_notifier_menu()
wp-includes/class-wp-hook.php:286
get_plugin_data()
wp-content/plugins/wp-advance-comment-pros/update-notifier.php:20
get_file_data()
wp-admin/includes/plugin.php:84
fread()
wp-includes/functions.php:4836

3. fclose() expects parameter 1 to be resource, boolean given

wp-includes/functions.php:4839
do_action(‘admin_menu’)
wp-admin/includes/menu.php:149
wpad_update_plugin_notifier_menu()
wp-includes/class-wp-hook.php:286
get_plugin_data()
wp-content/plugins/wp-advance-comment-pros/update-notifier.php:20
get_file_data()
wp-admin/includes/plugin.php:84
fclose()
wp-includes/functions.php:4839