Try with below code snippet it will resolve your issue -
Dim RA_File As String = "E:\XMLFile1.xml"
ComboBox1.Items.Clear()
Dim xmlDoc As XDocument = XDocument.Load(RA_File)
Try
For Each node As XElement In xmlDoc.Root.Descendants("RISKITEM")
ComboBox1.Items.Add(node.Attribute("NAME").Value)
Next
Catch ex As Exception
MsgBox(ex.Message)
End Try