Request.Form undefined on localhost but OK when ASP filed upl,oaded to web

I have an ASP page that implements a login function and has a form with a Login Name field and password field.  When the user clicks on the button it submits the form to another ASP page.  That page looks up the details in a database and logs the user in if OK.  All pretty standard stuff, and it works fine.  

However I thought I would speed things up b y developing it on the local machine instead of the edit/FTP/Test cycle.  So I installed IIS and it goes except that the contents of the Forms collection are all undefined.

when the files are on the web:

  Request.Forms ("LoginName")

returns a string containing whatever the user had typed in the field.

when the files are on the local machine:

  Request.Forms ("LoginName")

returns undefined.

what could be different?

heres the form:

<form name="LoginForm" action="membervalidate.asp?backto=<%=Server.URLEncode (Request.querystring ("backto")) %>" method="post">
  <input type="text" name="LoginName" size="16" maxlength="50">
  <input type="password" name="Password" size="16" maxlength="50">
</form>


and here is membervalidate.asp:

....
var Connection = OpenDatabase () ;
if (Connection != null)
    {
    Response.write (Request.Form ("LoginName") + "<br>") ;                            // writes "Undefined"
    Response.write (Request.Form ("LoginName").Item + "<br>") ;                    // writes "undefined"
....