LeanPress Plugin Error

When I use the LearnPress Plugin the CSS is getting messed up somehow. When I create a new lesson in the editor the formatting does not transfer over unless I allow comments in the Discussion box settings. However, when I allow comments I get the fatal error:Cannot redeclare hb_format_comment() (previously declared in /home1/learnht1/public_html/wp-content/themes/HighendWP/comments.php:123) in /home1/learnht1/public_html/wp-content/themes/HighendWP/comments.php on line 169

If I turn OFF comments in the discussion settings, the CSS looks good for the lesson, but the formatting does not carry over. I spoke with the LearnPress admins and they think there is something in the theme code that is causing the error.

Can someone please help with this? I’ve attached a screen shot.