Intellij PHP remote debugging: Failed to execute validation script

In my case the issue is the Apache Rewrite rules that when _intellij_phpdebug_validator.php get the redirect file in my case to a 404 page of Symfony framework installed for this project.

This problem appears if the 'Web Path' field under Tools | Deployment | Configuration | Mapping is not correctly pointing to the url at which the uploaded validator script is accessible.

Just download file

http://gist.github.com/litzinger/8fd06ab6e5033b7ff8d8

to your deployment directory or directly to target server document root directory