XmlDocument bind to treeview in Silverlight

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Silverlight

Hi All i am facing the same problem
can you please help me anybody on this.
I have wcf has returning the xelement with parents,child,subchild elements from that i want to bind to the treeview control as like parent,child ,subchild elements,
Please help me on this
this is wcf has retun as xelement from this i want to do find parent,child,subchild and bind to silverlight4 treeview.
here i am getting object reference not set error.

<?xml version="1.0" encoding="utf-8" ?>
<Regions>
  <Region name="Americas-01">
    <SubRegionOne name="LatinAmerica-05">
    </SubRegionOne>
    <SubRegionTwo name="MCA-60">
    </SubRegionTwo>
    <SubRegionThree name="CAC-37">
    </SubRegionThree>
    <Country name="HPEruope-14">
    </Country>
  </Region>
  <Region name="EMEA-02">
    <SubRegionOne name="LatinAmerica-05">
    </SubRegionOne>
    <SubRegionTwo name="MCA-60">
    </SubRegionTwo>
    <SubRegionThree name="CAC-37">
    </SubRegionThree>
    <Country name="HPEruope-14"></Country>
  </Region>
  <Region name="AsiaPacific-03">
    <SubRegionOne name="LatinAmerica-05">
    </SubRegionOne>
    <SubRegionTwo name="MCA-60">
    </SubRegionTwo>
    <SubRegionThree name="CAC-37">
    </SubRegionThree>
    <Country name="HPEruope-14"></Country>
</Region>
</Regions>

[DataContract]
    public class GeoDataProvider
    {
        [DataMember]
        public string Region { get; set; }
        [DataMember]
        public string SubRegionOne { get; set; }
        [DataMember]
        public string SubRegionTwo { get; set; }
        [DataMember]
        public string SubRegionThree { get; set; }
        [DataMember]
        public string Country { get; set; }
        [DataMember]
        public List<GeoDataProvider> GeoSubItems { get; set; }
    }     XDocument xDocument = XDocument.Load("Mpo_Admin.xml");
            GeoDatatSource = this.GetGeoSource(xDocument.Element("Regions"));
            GeotreeView.ItemsSource = GeoDatatSource;
        private List<GeoDataProvider> GetGeoSource(XElement element)
        {
            try
            {
                return (from Regiondata in element.Elements("Region")
                        select new GeoDataProvider()
                        {
                            Region = Regiondata.Attribute("name").Value,
                            SubRegionOne = Regiondata.Attribute("name").Value,
                            SubRegionTwo = Regiondata.Attribute("name").Value,
                            SubRegionThree = Regiondata.Attribute("name").Value,
                            Country = Regiondata.Attribute("name").Value,
                            GeoSubItems = this.GetGeoSource(Regiondata)
                        }).ToList();
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

Advanced thank you,
Regards,
Narasimha