To begin with Xwiki on an Intranet: first problem

Hi, I'm a new user of Xwiki. Actually, I'm testing it for the moment. I have a very first problem : I've just launched the XWiki service and logged in... When I edit the "Welcome to your Wiki" page and save, it's Ok : I see my modification in the page... But I try to edit it again, I am in the editing mode but I have the old version of the page, without the last modification... even if I reload the page in ie... It seems as a proxy was showing me an old page... Thanks for your help My profile : Win XP SP2 I installed XWiki by launching "xwiki-0-9-1000-alpha-setup.exe" file. I'm logged as Admin (= Xwiki)