SQL Server 2012 SSIS Script Task gives Error: Cannot load script for execution.

Script newbie here.  Trying to run a Script Task copied from http://www.nullskull.com/faq/1431/send-authenticated-smtp-email-from-ssis.aspx that will send email to an authenticated SMTP server (basic authentication).  Getting the error "Cannot load script for execution" before it can reach any breakpoints I've set in the script.  Running on Windows Server 2012 and SQL Server 2012.  Data tools and SSMS installed and useable for other things that haven't involved script tasks.  Run64BitRuntime set false (didn't work with True either).

Note there is a warning that: 'ScriptMain' is not CLS-compliant because it derives from 'VSTARTScriptObjectModelBase'.

Here's the script - down to just a do-nothing skeleton that still won't load.  Warning line indicated by <<<

Thanks for the help.

Imports System
Imports Microsoft.SqlServer.Dts.Runtime
Imports System.Net.Mail
Imports System.Net

Enum ScriptResults
    Success = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Success

    Failure = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Failure
End Enum

Public Class ScriptMain  ''<<<This line gives the warning about CLS compliance

    Inherits Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTARTScriptObjectModelBase

    Public Sub Main()

        Dim Message As MailMessage = New MailMessage()
        Dim Smtp As New SmtpClient()
        Dim SmtpUser As New System.Net.NetworkCredential()

        ' other code is normally here...

        Try
            Smtp.Send(Message)
            Dts.TaskResult = ScriptResults.Success

        Catch ex As Exception
            Dts.TaskResult = ScriptResults.Failure
        End Try
    End Sub
End Class