error message from VWD - literal ID is not declared

[Jon Paal]

When trying to change visibility of literal control ,
VWD keeps telling me " 'FailureText' is not declared" (blue squiggly line).
what's missing ?

<%@ Page Language="VB" %>
<script runat="server">
Public Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
If Page.IsPostBack = True Then
FailureText.Visible = True '<-- error here
End if
End Sub
</script>

....
<p class="warning">
<asp:Literal runat="server"
Visible="false"
ID="FailureText"
EnableViewState="False" />
</p>