Code doesn't work....error code of not declared, how is it fixed?

Public Class Form1

Private Sub btnShow_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnShow.Click ' Show the world. picWorld_Visible = True End Sub

Private Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click ' Close the form. Me.Close() End Sub End Class