I've found an issue in the file "inc/raf_form.php".
The wordpress environment loading in line 3 ("require_once( dirname(__FILE__) . '../../../../../wp-load.php' );") is not working if the "wp-content" directory has been moved to a different location.
For example in my configuration my structure is:
So as wp-content is not placed in the wp folder your relative path is broken. I manually changed it in the file but could you get it fixed in next release?