The Auth.Authenticate() does not check anything, the system react like the user is already log in ? Under IIS no problem .
Is there a trick in the http.conf of Apache.

PS : my authentication code

<%
Auth.AuthTable = "util_intranet.dbf"
Auth.Header = ';
<p align="center"><img border="0" src="BELFOR1.GIF" width="100" height="119"></p> ;
<center><font face="Arial" size="4" color="#FF0000">Vous entrez dans une zone sécurisé, tout les mouvements seront archivés<BR> veuillez vous authentifier.</center><P>'
Auth.Footer = '<br><font><I><font face="Arial" color="black"><center>&copy; Jesperson & Clerc  1998-'+allt(str(year(date())))+'</center></font></i>'
Auth.AuthformFile="AuthForm.fwx"
Auth.Useridfieldname="util"
Auth.Passwordfieldname="passe"
Auth.SaveCookie = 0
Auth.passwordcaption="Mot de Passe"
Auth.useridcaption="Utilisateur"
Auth.Authenticate()
response.redirect("menu_principal.fwx")
%>