Debug error

Every time I try to insert the widget into post and click on the next button, it won’t move. Besides, it also shows the debug error in the widget. Something like this:

Notice: Use of undefined constant ENT_HTML5 – assumed ‘ENT_HTML5’ in /home/buddyg5/public_html/buppha.com/wp-content/plugins/feedweb/feedweb_util.php on line 21

Notice: Use of undefined constant ENT_IGNORE – assumed ‘ENT_IGNORE’ in /home/buddyg5/public_html/buppha.com/wp-content/plugins/feedweb/feedweb_util.php on line 21
URL:

Notice: Use of undefined constant ENT_IGNORE – assumed ‘ENT_IGNORE’ in /home/buddyg5/public_html/b

My website is: http://buppha.com/

https://wordpress.org/plugins/feedweb/