发送邮件提示“未能访问“CDO.Message”对象。”

Public Function SendMail() As String
        Dim conf As New CDO.ConfigurationClass()
        Dim strEmailAddr As String
        Dim strReturn As String
        Dim array_strAttachment() As String = Split(strAttachment, ",")
        Dim i As Integer
        strEmailAddr = p_strSmtp.Replace("smtp.", p_strUserName & "@")
        Try
            conf.Fields(CdoConfiguration.cdoSendUsingMethod).Value = CdoSendUsing.cdoSendUsingPort
            conf.Fields(CdoConfiguration.cdoSMTPServer).Value = p_strSmtp
            conf.Fields(CdoConfiguration.cdoSMTPServerPort).Value = p_nSmtpPort
            conf.Fields(CdoConfiguration.cdoSMTPAccountName).Value = p_strUserName
            conf.Fields(CdoConfiguration.cdoSendUserReplyEmailAddress).Value = """" + p_strUserName + """<" + strEmailAddr + ">" + ""
            conf.Fields(CdoConfiguration.cdoSendEmailAddress).Value = """" + p_strUserName + """<" + strEmailAddr + ">" + ""
            conf.Fields(CdoConfiguration.cdoSMTPAuthenticate).Value = CdoProtocolsAuthentication.cdoBasic
            conf.Fields(CdoConfiguration.cdoSendUserName).Value = p_strUserName
            conf.Fields(CdoConfiguration.cdoSendPassword).Value = p_strPSW
            conf.Fields.Update()            Dim msg As New MessageClass()
            msg.Configuration = conf
            msg.To = p_strReceiver
            If Len(p_strCC) >= 0 Then
                msg.CC = p_strCC
            End If
            msg.Subject = p_strSubject
            msg.From = strEmailAddr
            For i = 1 To array_strAttachment.Length
                msg.AddAttachment(array_strAttachment(i - 1))
            Next
            If p_bHtml Then
                msg.HTMLBody = p_strBody
            Else
                msg.TextBody = p_strBody
            End If
            msg.Send()
            strReturn = p_strReceiver & "发送成功" & Now
        Catch er As System.Runtime.InteropServices.COMException
            strReturn = p_strReceiver & "发送失败" & Now
        End Try
        Return strReturn
    End Function