Value of type 'String' cannot be converted to 'System.Net.Mail.MailMessage'

Hi
I have an issue in sending email using Asp.net. I do not know where I did wrong. Error is Value of type 'String' cannot be converted to 'System.Net.Mail.MailMessage'
Pls advice me
Web.Confi
<system.net> <mailSettings> <smtp from="xxxxxxx@gmail.com"> <network host="smtp.gmail.com" password="xxxxxx" userName="xxxxxx@gmail.com" enableSsl="true" port="587"/> </smtp> </mailSettings> </system.net>
Function
Private Function PopulateBody() As String Dim body As String = String.Empty Dim reader As StreamReader = New StreamReader(Server.MapPath("comlaint_log.html")) body = reader.ReadToEnd body = body.Replace("{Date} ...