Object Reference Not Set To An Instance Of An Object. Error Will Shown In This Code?

When i run the following code it the error as :

""Object reference not set to an instance of an object.""
Protected Sub CreateUserWizard1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles CreateUserWizard1.Load
Dim SQLData As New System.Data.SqlClient.SqlConnection("Data Source=.SQLEXPRESS;AttachDbFilename=|DataDirectory|ASPNETDB.MDF;Integrated Security=True;User Instance=True")
Dim cmdSelect As New System.Data.SqlClient.SqlCommand("SELECT TOP 1 EmployeeId FROM a1_admins Order by Id DESC", SQLData)
Dim label11 As Label = CreateUserWizard1.CreateUserStep.ContentTemplateContainer.FindControl("Label11")
SQLData.Open()
Dim dtrReader As System.Data.SqlClient.SqlDataReader = cmdSelect.ExecuteReader()
If dtrReader.HasRows Then
While dtrReader.Read()
label11.Text = dtrReader("EmployeeId")
End While
End If
dtrReader.Close()
SQLData.Close()
End Sub
End Class