esse é certo:
Global.asa
<script LANGUAGE="VBScript" RUNAT="Server">
Sub Application_OnStart
application("activevisitors")=0
End Sub
Sub Application_OnEnd
End Sub
Sub Session_OnStart
application.lock
application("activevisitors")=application("activevisitors")+1
application.unlock
End Sub
Sub Session_OnEnd
application.lock
application("activevisitors")=application("activevisitors")-1
application.unlock
End Sub
</SCRIPT>
Esse vc coloca na sua pagina:
<% =application("activevisitors") %>
Obs: a pagina deve estar no mesmo diretório do global.asa
Abraços