I just installed prestashop and the istallation went smoothly but I cant enter the back office. every time I login it redirects to the same login page. (it always directs to http://mysite.com/shop/admin/login.php?redirect=index.php). I've tried clearing my cookies/caches, checked my login.php file, and nothing seems to work. Hope someone can help me, its frustrating. I dont really know whats wrong. thanks!