Use of CDO code to send emails failing

I have written an application to be used by our Seniors Captain at the Golf Club. It allows him to email Teamsheets to select players directly from Excel using Outlook. I want to adapt the application to use other mail packages other than Outlook.
Using code supplied from Ron de Bruin's Web site I used this test program to test out the method.

Sub CDO_Mail_Small_Text()
    Dim iMsg As Object
    Dim iConf As Object
    Dim strbody As String
        Dim Flds As Variant

    Set iMsg = CreateObject("CDO.Message")
    Set iConf = CreateObject("CDO.Configuration")

        iConf.Load -1    ' CDO Source Defaults
        Set Flds = iConf.Fields
        With Flds
            .Item("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2
            .Item("http://schemas.microsoft.com/cdo/configuration/smtpserver") _
                           = "my.server.co.uk"
            .Item("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 25
            .Update
        End With

    strbody = "Hi there" & vbNewLine & vbNewLine & _
              "This is line 1" & vbNewLine & _
              "This is line 2" & vbNewLine & _
              "This is line 3" & vbNewLine & _
              "This is line 4"

    With iMsg
        Set .Configuration = iConf
        .To = "my@email.address.uk"
        .CC = ""
        .BCC = ""
        .From = """Dave"" <my@email.address.uk>"
        .Subject = "New figures"
        .TextBody = strbody
        .Send
    End With

End Sub

With Port smtpserverport set to 25, I get this error message
Run-time error '-2147220978(8004020e)':
The server rejected the sender address. The server response was: 550 Access denied - Invalid HELO name (see RFC2821.4.1.1.1)

With the smtpserverport set to 465 I get
Run-time error '-2147220978(80040213)':
The transport failed to connect to the server
The code above was used on a computer using Outlook.
My Outlook application uses port 465.


I got the same result from a laptop using Windows Live Mail.

Can anyone tell me what is wrong?
Dave