A machine.config error when I try to send an e-mail from an aspx page

[cesark]

I have an aspx page that send an email to the user, and until now it worked, but now I receive an error. This is the sub and the error:

Sub send_Password(Sender As Object, E As ImageClickEventArgs)
If (Page.IsValid) Then

Dim CmdPassword As New SqlCommand("return_Password", strConnection)
CmdPassword.CommandType = CommandType.StoredProcedure

CmdPassword.Parameters.Add(New SqlParameter("@e_mail", SqlDbType.varchar, 50, "e_mail"))
CmdPassword.Parameters("@e_mail").Value = mail.Text()

CmdPassword.Parameters.Add("@Resp", SqlDbType.TinyInt)
CmdPassword.Parameters("@Resp").Direction = ParameterDirection.Output

CmdPassword.Parameters.Add("@Password", SqlDbType.varchar, 8)
CmdPassword.Parameters("@Password").Direction = ParameterDirection.Output

strConnection.open()
CmdPassword.ExecuteNonQuery
Dim Response As byte = CmdPassword.Parameters("@Resp").Value
strConnection.close()

If (Resonse = 1) Then
Dim E_mail As New MailMessage()
E_mail.To = mail.Text()
E_mail.From = """Cesar"" <cesar_bla@mydom.com>"
E_mail.Subject = "Access Data - MySite.com"
E_mail.Body = "Your access code is: " & CmdPassword.Parameters("@Password").Value
E_mail.Priority = MailPriority.Normal

try
SmtpMail.SmtpServer = "mail.infomail.es"
SmtpMail.Send(E_mail)
Response.Redirect("forgotten_code_ok.aspx")

catch exc as Exception
Message.Text() = "An error happened."
End Try

Else
Message2.Text() = "None user was found with these credentials."
End If

End If
End Sub



And the server error message:
The XML file c:\winnt\microsoft.net\framework\v1.1.4322\Config\machine.config could not be loaded. Attempted to access an unloaded AppDomain.
Source Error: [No relevant source lines]

How can I solve it?

Thanks