Some of the previously collected information---a mailing list using CDO ASP program (admin side)

This is the entire mailing list program server, run by the manager:
FileName mailadmin.asp:
<%
' When using this code, please send all mailing lists (suffix lst) files and
The ' Letter file (suffix ltr) is placed in the root directory Basedir and guarantees write permission to the directory
Dim Debug
debug = False
BASEDIR = Server.MapPath ("/tmp/maillist")
Forreading = 1
ForWriting = 2
ForAppending = 8
' Separator character
delimiter = "|"
' URL Note For this code is not a path
Script_url= "Mailadmin.asp"
' The CDO NTS used in the code to send mail
' $DEFAULT _email is the variable to hold the default return address (can be modified as appropriate)
Default_email= "Yourname@yourmailserver"
CPR = ""
If StrComp (Request.ServerVariables ("Request_method"), "POST", vbTextCompare) <> 0 and _
StrComp (Request.ServerVariables ("query_string"), "", vbTextCompare) = 0 Then
Query_form
Response.End
End If
If StrComp (Request.ServerVariables ("Request_method"), "POST", vbTextCompare) = 0 and _
Request.Form ("action") = "LIST" Then
Get_list
Response.End
End If
If StrComp (Request.ServerVariables ("Request_method"), "POST", vbTextCompare) = 0 and _
Request.Form ("action") = "SENDMAIL" Then
Send_mail
Response.End
End If
If StrComp (Request.ServerVariables ("Request_method"), "POST", vbTextCompare) = 0 and _
Request.Form ("action") = "Postletter" Then
Post_letter
Response.End
End If
If StrComp (Request.ServerVariables ("Request_method"), "POST", vbTextCompare) = 0 and _