Undefined index:post_type error encountered on Add New Post page

We installed this plug-in over the past weekend and are now seeing the following error occur on the Add New Post page (child them of TwentyFourteen theme with style.css and footer.php overrides):

Notice: Undefined index: post_type in /usr/home/<em>myuser</em>/www/<em>mysite</em>/wp-content/plugins/header-footer/admin.php on line 67

The problem does not block the adding of a post, but is persistent.

https://www.ads-software.com/plugins/header-footer/