My apologies, I have actually found the problem! I was able to reproduce it on one of my test servers. On the main plugin file there was an opening and closing php tag between the comment and the code and apparently some php versions are not tolerating that!
I'm uploading the fixed version to codecanyon, while it gets approved you can download it from an attachement to this post. After deleting the old plugin, it should now work fine.Best,
If you like my products, don't forget to rate them on codecanyon :)