Variable Nuid Is Used Before Being Assigned A Value

I am trying to access a user's login credentials to find out if they are an admin user or not. This way I can assign session variables to them and show certain aspects of the web page that other users won't see. I unfortunately keep getting this error when trying to dim a variable to assign the values too.

Variable Nuid is used before being assigned a value.
Variable AdminUser is used before being assigned a value.

Code:
Protected Sub checkAdmin_Click(sender As Object, e As EventArgs) Handles checkAdmin.Click
Dim strNuid As String = Request.Form("Nuid")
Dim cnString As String = ConfigurationManager.ConnectionStrings("snfTimeSystemConnectionString").ToString()
Try
Using cn As SqlConnection = New SqlConnection()
cn.ConnectionString = cnString

[Code] .....