Error after upgrading

Hi guys. I just upgraded and after the plugin reactivated this line of code shows up at the top of my admin panel and my website pages

age']) ){if ( preg_match('/optin/', $page ) ) {return true;}}return false;} ?>

Please let me know what I should do to fix this so that I can enable the plugin again.

Thanks,
Justin

https://www.ads-software.com/extend/plugins/optin-revolution/