how to send file (local path) using wwwForm on iOS and Android?

Hey Peeps

We are trying to upload a file a video file on Facebook using wwwForm but i don't think i have the correct local path for the device.

here is the code we are using:

 public void PostVideo(string VideoLocStr)
 {
     Debug.Log (VideoLocStr);
     this.StartCoroutine(this.StartVideoUpload(VideoLocStr));
 }

 private IEnumerator StartVideoUpload(string VideoLocStr)
 {
     yield return new WaitForEndOfFrame();

     WWW www = new WWW("file:///Users/" + VideoLocStr);
     while(!www.isDone) {
         yield return null;
         Debug.Log("progress : "+www.progress);
     }
     Debug.Log("size : "+www.size);
     var wwwForm = new WWWForm();
     wwwForm.AddBinaryData("file", www.bytes, "Video.MOV","multipart/form-data");
     wwwForm.AddField("title", "Hello World");
     wwwForm.AddField("description", "How you doing?");

     FB.API("123456789/videos", HttpMethod.POST, UploadFinish, wwwForm);
 }

This is the error that it spits out:

 result : [BaseResult: Error=bad request, Result=System.Collections.Generic.Dictionary`2[System.String,System.Object], RawResult={"error":{"message":"There was a problem uploading your video file. Please try again.","type":"OAuthException","code":381,"error_subcode":1363021,"is_transient":false,"error_user_title":"Video Upload Problem","error_user_msg":"There was a problem uploading your video. Please try again.","fbtrace_id":"DIY4Zuvn0bO"}}, Cancelled=False] , error : bad request

can't find any information on the error searching with google or on the Facebook developer website.

Does anyone know what the correct file path should be for iOS and Android?

Thank you for your time.

Kind Regards