Got an crawl error on webmaster - /wp-app.php/service

Today on one of my blogs, I found an crawl error through Google webmaster. It says www.yourdomain.com/wp-app.php/service has a HTTP 403 error. Does anyone got this error?

403 is “Forbidden”

Seems normal and expected enough to me. If you have a link to a file that requires authentication you don’t want bots to get it.