response = (HttpWebResponse)request.GetResponse();
                reader = new StreamReader(response.GetResponseStream());
                String streamedXML = reader.ReadToEnd(); //
                XmlDocument doc = new XmlDocument();
                doc.LoadXml(streamedXML);

Unexpected end of file has occurred. The following elements are not closed:

using (var client = new WebClient())
{
     string streamedXML = client.DownLoadstring(sourceUrl);
     ...

}

using(response = (HttpWebResponse)request.GetResponse())
using(reader = new StreamReader(response.GetResponseStream()))
{
    String streamedXML = reader.ReadToEnd(); //
    XmlDocument doc = new XmlDocument();
    doc.LoadXml(streamedXML);
}