Greetings
I'm a bit low on free time myself...

...So I didn't do any cleaning on this code to hack it down to the bare essentials, but I know it works.
The below code sample (Which I googled for) shows how to do the basic file operations (read/write/create/delete) in asp. It will (/should) work on your server with only 2 changes if the page is located in site root.
1. You need to create a folder called data in the site root (which it writes the file to).
2. You need to grant the Full Control NTFS permission to the IGA
for the Data folder only.
Obviously item 2 is bad form for proper server security, but that can be dialed it later after you get what you want working to work. I as I recall you already know about the whole file permission game so there is no point on my lecturing you on that.

CODE
<%@ LANGUAGE="VBScript" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<% '***************************************************************************
'* ASP File Operations *
'* *
'* Do not remove this notice. *
'* *
'* Copyright 1999, 2000 by Mike Hall. *
'* Please see http://www.brainjar.com for documentation and terms of use. *
'***************************************************************************
'Set file I/O constants.
Const ForReading = 1
Const ForWriting = 2
Const ForAppending = 8
'Map the file name to the physical path on the server.
filename = "temp.txt"
path = Server.MapPath(".") & "\data\" & filename
'Get requested operation, if any.
operation = Request.Form("operation") %>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>ASP File Operations Demo</title>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<link rel="stylesheet" type="text/css" href="/common/default.css" />
</head>
<body>
<div id="demoBox">
<h3>ASP File Operations Demo</h3>
<p>Select a file operation below, the action will be performed against a text
file named '<a href="data/<% = filename %>"><% = filename %></a>' and the
contents will be displayed.</p>
<p>Note that the file may be suddenly changed or deleted if any one else
happens to be performing operations against it.</p>
</div>
<form action="<% = Request.ServerVariables("SCRIPT_NAME") %>" method="post">
<p>
<input name="operation" type="radio" value="create" /> Create
<input name="operation" type="radio" value="delete" /> Delete
<input name="operation" type="radio" value="read" checked="checked" /> Read
<input name="operation" type="radio" value="write" /> Write
<input name="operation" type="radio" value="append" /> Append
</p>
<p>
<input type="submit" value="Submit" />
<input type="reset" value="Reset" />
</p>
</form>
<p>
<% 'Perform the request operation.
if operation = "create" then
CreateFile(path)
ReadFile(path)
elseif operation = "delete" then
call DeleteFile(path)
elseif operation = "read" then
call ReadFile(path)
elseif operation = "write" then
call WriteFile(path)
ReadFile(path)
elseif operation = "append" then
call AppendFile(path)
ReadFile(path)
end if %>
</p>
</body>
</html>
<% sub CreateFile(path)
dim fs, file
Response.Write("<b>CreateFile:</b><br>")
set fs = CreateObject("Scripting.FileSystemObject")
'If the file already exists give an error message.
if fs.FileExists(path) then
Response.Write("File " & filename & " already exists, create aborted.<br>" & vbCrLf)
'Otherwise create it and write some data to it.
else
Response.Write("Creating " & filename & ".<br>")
set file = fs.CreateTextFile(path)
Response.Write("Writing data to " & filename & ".<br>")
file.WriteLine("Line 1 added " & Now() & ".")
file.WriteLine("Line 2 added " & Now() & ".")
file.WriteLine("Line 3 added " & Now() & ".")
file.WriteLine("Line 4 added " & Now() & ".")
file.WriteLine("Line 5 added " & Now() & ".")
file.Close()
end if
end sub
sub DeleteFile(path)
dim fs, file
Response.Write("<b>DeleteFile:</b><br>")
set fs = CreateObject("Scripting.FileSystemObject")
'If the file doesn't exist give an error message.
if not fs.FileExists(path) then
Response.Write("File " & filename & " does not exist.<br>")
'Otherwise delete it.
else
Response.Write("Deleting " & filename & ".<br>")
fs.DeleteFile(path)
end if
end sub
sub ReadFile(path)
dim fs, file
Response.Write("<b>ReadFile:</b><br>")
set fs = CreateObject("Scripting.FileSystemObject")
'If the file doesn't exist give an error message.
if not fs.FileExists(path) then
Response.Write("File " & filename & " does not exist, read aborted.<br>")
'Otherwise, open it and display the contents.
else
set file = fs.OpenTextFile(path, ForReading)
Response.Write("Reading " & filename & ".<br>")
Response.Write("<pre>")
do while not file.AtEndOfStream
Response.Write(file.ReadLine & vbCrLf)
loop
Response.Write("</pre>")
file.Close()
end if
end sub
sub WriteFile(path)
dim fs, file
Response.Write("<b>WriteFile:</b><br>")
set fs = CreateObject("Scripting.FileSystemObject")
'If the file doesn't exist give an error message.
if not fs.FileExists(path) then
Response.Write("File " & filename & " does not exist, write aborted.<br>")
'Otherwise, overwrite the contents.
else
set file = fs.OpenTextFile(path, ForWriting)
Response.Write("Rewritng file " & filename & ".<br>")
file.WriteLine("Rewriting file with line 1 added " & Now() & ".")
file.WriteLine("Rewriting file with line 2 added " & Now() & ".")
file.WriteLine("Rewriting file with line 3 added " & Now() & ".")
file.Close()
end if
end sub
sub AppendFile(path)
dim fs, file
Response.Write("<b>AppendFile:</b><br>")
set fs = CreateObject("Scripting.FileSystemObject")
'If the file exists, check its size and exit if it exceeds 500K.
if fs.FileExists(path) then
set file = fs.GetFile(path)
if file.size > 300 then
Response.Write("Size limit exceeded for file " & filename & ", append aborted.<br>")
exit sub
end if
'If the file doesn't exists, give a informational message.
else
Response.Write("File " & filename & " does not exist, will create.<br>")
end if
'Open or create the file as needed and append a line to it.
Response.Write("Appending line to " & filename & ".<br>")
set file = fs.OpenTextFile(path, ForAppending, true)
file.WriteLine("New line added " & Now() & ".")
file.Close()
end sub %>
I'll keep this as a running sample on my intranet webserver so we can work on tweaking it to your needs, after you get it to run (which I'm assuming or at least hoping it will).