set imagbutton url code behind

I understand that I need to set this on the page load event, but its not working, I am getting the loaction of the file, and I am able to click on the image but nothing happens.  What am I doing wrong here.
 
 
<tr> <td>ATTACHMENTS:</td> <td><asp:ImageButton ID="imgpdf" runat="server" ImageUrl="~/Images/pdf.png" Width="20px" Height="20px" BorderStyle="None" /></td> </tr> Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load If Not IsPostBack Then Dim leaseid As Integer = Convert.ToInt32(Request.QueryString("Lease")) 'Build the lease and Create it in draft format PrintDraftLease(leaseid) Dim target As String = Server.MapPath("~/PDFTemp/") sql = "S ...