[AccessD] Code Not Working in XP

I have been using the code shown below to access data on our Intranet. The
code matches a field entry in the database and looks up the details. In this
example it finds a stock number.
 
Problem: The code does not work for users that are running XP. It does not
do anything, it will not even try to access the web. They click the button
and nothing happens.
 
What can I do to correct this for users of XP?
 
Virginia
  _____  

 
  strPath = " http://web.com/vr.asp?xml=orafin%2Stock=
<http://webapps.pgdp.usec.com/vr/vr.asp?xml=orafin%2Fsistock&ParamStock=> "
   
   strFile = strPath & Me.StockNumber
 
   If Dir(strFile) = "" Then
      strFile = strPath & Me.StockNumber
   End If
 
   Call fHandleFile(strFile, WIN_MAX)