node in xml file not deleting

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VB

hi my xml file is

<?xml version="1.0"?>
<Root>
  <FileName Name="RootProcess">
    <Id>727683220</Id>
    <FileName>adsf</FileName>
    <FilePath>d:\manohar\adsf.xml</FilePath>
    <Description>fsad sdfa</Description>
  </FileName>
  <FileName Name="PlantProcess">
    <Id>1362537878</Id>
    <FileName>PlantProcess</FileName>
    <FilePath>PlantProcess</FilePath>
    <Description> sdf sdf</Description>
  </FileName>
  <FileName Name="LogData">
    <Id>1362537878</Id>
    <FileName>LogData</FileName>
    <FilePath>PlantProcess</FilePath>
    <Description> sdf sdf</Description>
  </FileName>
</Root>

my code is

If (IO.File.Exists(Server.MapPath("~/App_Data/XMLFile.xml"))) Then
           For Each gvrow As GridViewRow In dgvXmlPathSetting.Rows
               'Finiding checkbox control in gridview for particular row
               Dim chkdelete As CheckBox = DirectCast(gvrow.FindControl("chkdelete"), CheckBox)
               'Condition to check checkbox selected or not
               If chkdelete.Checked = True Then
                   'Getting UserId of particular row using datakey value
                   Dim lblId As Label = DirectCast(gvrow.FindControl("lblId"), Label)
                   Dim FileName As Label = DirectCast(gvrow.FindControl("lblFIleName"), Label)

                   Dim xmldoc As New XmlDocument()
                   xmldoc.Load(Server.MapPath("~/App_Data/XMLFile.xml"))
                   Dim nodes As XmlNodeList = xmldoc.SelectNodes("//Root/FileName[@Name='" & FileName.Text.Trim() & "']")
                   'Dim nodes As XmlNodeList = xmldoc.SelectNodes("/Root/FileName[@Name="" & FileName & ""]")
                   For i As Integer = nodes.Count - 1 To 0 Step -1
                       nodes(i).ParentNode.RemoveChild(nodes(i))
                   Next
                   '  reader.Close()
                   xmldoc.Save(Server.MapPath("~/App_Data/XMLFile.xml"))
               End If
           Next
           loadXmlToGridview()
       End If

in xmldoc.save error is coming

The process cannot access the file 'D:\Manohar\srsConnect\App_Data\XMLFile.xml' because it is being used by another process.

can anyone help