Perhaps this will solve some of the problems listed here: create an .htaccess file in your root directory and add this to it:
<Files xmlrpc.php>
SecFilterInheritance Off
</Files>???
This assumes, of course, that your xmlrpc.php file is present in the root directory also.
For me, this was a quick and effective fix for this jetpack error message as well as other confusing connection errors involving remote posting on a self-hosted wp site (e.g., blogpress for iOS). Hope this helps!
