Acurax Advanced Slideshow Manager Install Problem

I have purchased Acurax Advanced Slideshow Manager, and it appears to install OK, but Wordfence security has issued the following message

“This file may contain malicious executable code: /hermes/waloraweb002/b439/moo.bcasey1940/wp-content/plugins/advanced-acx-slideshow-manager/slideshow-licence.php
Filename: wp-content/plugins/advanced-acx-slideshow-manager/slideshow-licence.php
File type: Not a core, theme or plugin file.
Issue first detected: 13 hours 56 mins ago.
Severity: Critical
Status New
This file is a PHP executable file and contains an eval() function and base64() decoding function on the same line. This is a common technique used by hackers to hide and execute code. If you know about this file you can choose to ignore it to exclude it from future scans.”

Wordfence repeats this for 6 more files:
acx_slideshow_managegallery.php
acx_slideshow_option.php
advanced-slideshow-manager-misc.php
advanced-acx-slideshow-manager/functions.php
rename_gallery.php
acx_slideshow_generate_shortcode.php

My slideshow doesn’t appear – just a blank page.

The webpage is https://www.wtcasey.net/new-york-august-2014/

I assume that Wordfence is blocking something from installing. Is there a security problem with the code in these files? What should I do?

Thanks
Bill Casey