Fatal Error when activating

when I try to activate this plugin I get the following fatal error:

Fatal error: Cannot access self:: when no class scope is active in /home/content/91/7094991/html/blog/wp-content/plugins/simple-photos-contest/simple-photos-contest.php on line 34

I’m using the latest version available through the wordpress plugin site.

https://www.ads-software.com/extend/plugins/simple-photos-contest/