Undefined property error

Hi,

I am facing Undefined property error on my website because of this plugin. Due to the error, I am unable to see my media library. When I deactivate the plugin, it goes from the website and my media library works properly but after activating the plugin, the error and problem comes again. This is the image link: https://www.dropbox.com/s/4a7w6neic3kqw0j/Screenshot%202018-02-28%2020.46.30%20copy.png?dl=0

The page I need help with: [log in to see the link]