treeview findnode error ??

I am trying to locate a node as a second level in my tree , but im getting an error  
Object reference not set to an instance of an object.
my code is below any help to let this code work wilb be veryyy appreciated 

MenuItem selectedItem = Menu1.SelectedItem; Response.Write("You selected " + Menu1.SelectedItem.Text + "."); getvalue.Text = Menu1.SelectedItem.Text; TreeView1.FindNode("Georges\\getvalue.Text").Expand();