I get this error when I am creating myXmlNodeReader object. I am confused. i have already declared the variable and now I am creating an instance of XmlNodeReader object. why shouuld I get this error? thanks

I have declared this variable as public scope.

public XmlNodeReader myXmlNodeReader;

public XmlNodeReader LoadXmlDoc()

{

XmlDocument myXmlDocument = new XmlDocument();

myXmlDocument.Load(@"c:\web.config");

ADgroups = new List<string>();

myXmlNodeReader = new XmlNodeReader(myXmlDocument.SelectSingleNode("configuration//appSettings"));

return myXmlNodeReader;