Wenn bestimmter Text resp. Knoten in XML Datei bereits vorhanden dann script nicht ausfürhen

Dim objShell,appdata
Set objShell = CreateObject("wscript.shell")  
appdata = objShell.ExpandEnvironmentStrings("%appdata%")  
Set xmlDoc = CreateObject("Microsoft.XMLDOM")  
xmlDoc.async = False
xmlDoc.load(appdata & "\Microsoft\FSX\dll.xml")  
If xmlDoc.SelectSingleNode("//Name[.=""ATi Core""]") is Nothing then  
    Set xmlRoot = xmlDoc.documentElement
    Set xmldll = xmlDoc.createElement("Launch.Addon")  
    Set xmlKnoten = xmlDoc.createElement("Name")  
    xmlKnoten.Text = "ATi Core"  
    xmldll.appendChild(xmlKnoten )
    Set xmlKnoten = xmlDoc.createElement("Disabled")  
    xmlKnoten.Text = "False"  
    xmldll.appendChild(xmlKnoten)
    Set xmlKnoten = xmlDoc.createElement("ManualLoad")  
    xmlKnoten.Text = "False"  
    xmldll.appendChild(xmlKnoten )
    Set xmlKnoten = xmlDoc.createElement("Path")  
    xmlKnoten.Text = "ATi\ATi CoreX.dll"  
    xmldll.appendChild(xmlKnoten )
    xmlRoot.appendChild(xmldll)
    xmlDoc.Save(appdata & "\Microsoft\FSX\dll.xml")  
End if
Set xmlDoc = Nothing