Problem with a Sub's Argument

[JDP]

I have a Form with a number of Panels and each panel contains a large number of labels and pictureboxes.

When the user clicks on any label, I want the text forecolor of all the labels in that particular panel to change to another color .

I thought I could do it with this Sub, but it throws an error :-

Private Sub ChangePanelTextColor(ByRef PN As Panel)
        Try
            Dim l As Label
            For Each l In PN.Controls
                l.ForeColor = System.Drawing.Color.BurlyWood
            Next

                   Catch ex As Exception
            MessageBox.Show(ex.ToString)
        End Try

    End Sub

and I called it from a Label_Click event in the usual way

ChangePanelTextColor(<Name of Panel containing this Label>)

Have I missed something really obvious and basic here ? Or do I have to go about it in a completely different way?

JDP