Fatal error when saving gallery edits

When I try to save my edits to a gallery, I get this message:

Fatal error: Call to a member function settings() on a non-object in ******/wp-content/plugins/photoshow/photoshow.clss.php on line 200

Please let me know how to resolve the problem.

Thanks for your help,

https://wordpress.org/plugins/awesome-flickr-gallery-plugin/