404 not found when logging in to admin for first time...

Hi, I am a newbie to zen cart and am looking for some help. I have installed zen cart successfully on an XAMPP server on my Mac and have completed the setup as per tutorial and installation guide.'however when I go to login to my new admin (now called 'ad') director I get a 404 item not found error. Has anyone else seen this before. Any help appreciated. I may also be worth noting that I have had the same thing happen on other hosting servers too so it seems not to be an XAMPP server issue but rather a "me" issue. Thanks!!