refactored a bit. In this scenario I needed to assign the postdata information to an object as such below. also needed to stop using facebooksharp, their api does weird stuff to the request.
var obj = new
{
app_id = appId,
type = app_name:object_type",
url = Url,
title = Name,
image = Image,
video = Video,
description = Description
};
var vars = new NameValueCollection {{"object", JsonConvert.SerializeObject(obj)}, {"format", "json"}, {"access_token", AppToken}};
var url = "https://graph.facebook.com/app/objects/"+ _appName + object_type;
return HttpTools.Post(url, vars);