Problems with header("Location:...") . . .

Hi! First, sorry if what I'll ask you was discussed in another occasion. I working in a simple page ("index.php") that shows 3 frames ("top","menu" and "main"). In the "main" frame, there is a form where the users execute your logon. Well, once he is authenticated, his profile are created and the "index.php" must be reloaded. The problem is that "index.php" is reloading in the "main" frame, not in "_top" (like "<a href=bla.php target=_top>"). There´s a way to do that using "header('Location:...')". Have you another way to do that? Thanks for your help! []s Cesar.