Jetpack Error

Hey,
When I’m trying to install Jetpack plugin, I get a error like that:

The Jetpack server could not communicate with your site’s XML-RPC URL. Please check to make sure http://www.idevice.co.il/xmlrpc.php is working properly. It should show ‘XML‑RPC server accepts POST requests only.’ on a line by itself when viewed in a browser and should not have any blank links or extra output anywhere.

I haven’t any Firewall plugins or somgthing like that….

Please help me!

http://wordpress.org/extend/plugins/jetpack/