How To Show A Stored PDF

New to asp and have no idea what I'm doing wrong here. I just want to open a pdf that I have stored in a table and show it on the page. Here is my code. I keep getting the System.NullReferenceException was unhandled by user code.

<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:smithsdaConnectionStringtest %>"

ProviderName="<%$ ConnectionStrings:smithsdaConnectionStringtest.ProviderName %>"

SelectCommand="SELECT * FROM [correspondence] WHERE ([facilitiesID] = ?)">

<SelectParameters>

<asp:QueryStringParameter Name="facilitiesID" QueryStringField="DACorr" Type="Int32" />

</SelectParameters>

</asp:SqlDataSource>

 

<script runat="server">Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)

 Dim ScanDoc As New DataViewDim arg As New DataSourceSelectArguments

ScanDoc = SqlDataSource1.Select(arg)

Dim ScanLet(1) As ByteScanLet(0) = CByte(ScanDoc(0)("Letter"))

 

If ScanDoc IsNot "" Then

Response.Buffer = True

Response.Clear()

Response.ClearContent()

Response.ClearHeaders()

Response.ContentType = "application/pdf"

Response.BinaryWrite(ScanLet)

Response.End()

End IfEnd Sub

</script

 Any Help greatly appreciated.