Facebook SDK on the Windows 7 Phone Casts (OAuthException) (# 210) User Not Displaying

I am using the Facebook SDK (Codeplex) on Windows Phone 7.

When I try to write to Friends Wall, I get this exception ((OAuthException) (# 210) User is not displayed)

Below is my request

private string requestedFbPermissions = "user_about_me,publish_stream";
//
var parms = new Dictionary<String, object>();
parms["display"] = "touch";
parms["client_id"] = apiKey;
parms["scope"] = requestedFbPermissions;
parms["type"] = "user_agent";

try
{
    string feedRequest = selectedUID + "/feed?message=\'Test Msg\'";

    fbApp.PostAsync(feedRequest, parms, (value) =>
    {
        object result = value.Result;
        JObject stuff = JObject.Parse(value.Result.ToString());
    }
}

Something is missing for me, for some friends I can successfully write on the wall.