/Jsource/Jmail/mailing_pro.asp 소스에
if "6.0" = right(Request.ServerVariables(41),3) then

      Set objmail = Server.CreateObject("CDO.Message")
      objmail.To  = To_email
      objmail.From = From_name & "<" & From_email & ">"
      objmail.Subject = Title

      select case tag
      case "0"
        'objmail.body = Message
        'objmail.bodyformat = 0
        'objmail.mailformat = 0
        
        objmail.HTMLBody = Message

      case else
        'objmail.body = Message
        'objmail.bodyformat = 1
        'objmail.mailformat = 1
        objmail.TEXTBody = Message
      end select

이 부분에서 에러가 나더라구요. 그래서 objmail.HTMLBody = Message 로 대신해주니 잘되더군요.
참고해주세요~