Hey – not the plugin author, but I just ran into the same issue.
The problem is that set_magic_quotes_runtime() was deprecated in PHP 5.3, but still available. In this case, the plugin would still run, but just display the above error. However, it was completely removed in PHP 7.0, so if you’re running WordPress using PHP 7, this line will cause the plugin to fail.
The simple fix is just to open the file, remove that line, and save the file. Removing it doesn’t have any negative repercussions because the intention for the function is achieved by its removal from PHP.
