HTTP 406

From my R/3 System(Async - IDOC) we need to send a request to an URL(Synchronous - HTTP) and need to bring the Response Back to a File System.

I have completely configured the necessary objects in XI(it includes BPM too).

Now I am receiving a response from the URL and inside the XI Message Monitoring it says error, but inside the file system I am seeing an HTTP Return code 406.

I got the 406 error from various site(http://www.checkupdown.com/status/E406.html) but I don'tknow whats exactly wrong or how to resolve that.

Any help.