Prova così:

codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Un'area riservata con minifloppy.it</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<body>
<% 
if Request.Form("inviato") = "si" then

	Dim strnick, strpsw
	
	strnick = Trim(Replace(Request.Form("nick"), "'", ""))
	strpsw = Trim(Replace(Request.Form("psw"), "'", ""))
	
	if strnick <> "" AND strpsw <> "" then
		dim objConn, objRs, strSql
		
		objConn.Open "driver={Microsoft Access Driver (*.mdb)};dbq="& server.MapPath("../../mdb-database/aliwork_shop.mdb")
		set objConn = Server.CreateObject("ADODB.Connection")
		set objRs = Server.CreateObject("ADODB.RecordSet")
		strSql = "SELECT * FROM utenti WHERE nick='"& strnick &"' AND psw='"& strpsw &"';"
		objRs.open strSql, objConn, 1, 3
		if not objRs.eof then
			Session("nick") = objRs("nick")
			Session("psw") = objRs("psw")
			%> 
			Login effettuato con successo.
			<% 
		else
			%> 
			Login fallito. Nome utente e/o password sconosciuti.			<% 
		end if
		
		objRs.close
		objConn.close
		set objRs = nothing
		set objConn = nothing
	else
		%> 
		I dati inseriti non sono corretti... riprovare.
		<% 
	end if

else
	%> 
	<form name="login" action="login.asp" method="post">
	Area riservata

	Nick: <input type="text" name="nick">

	password: 
	<input name="psw" type="password" id="psw">
	

	<input type="hidden" name="inviato" value="si">
	<input type="submit" value="Loggati">
	</form>
	<% 
end if
	%> 
</body>
</html>