PHP help, please...

Hello,

I put a product on CB a week or so ago and started getting affiliates and watched the hop count grow but noticed that google analytics was nowhere near that count.

Today I was updating the sales page and after uploading I noticed it didn't update by trying to look at it using my affiliate url path.

http://mysite.com/421/?pid1

So I noticed that the same sales page was also in the same location on my server.
http://mysite.com/421/salespage.htm

So I thought that the php script in my root folder was defaulting to the .htm page so I took it out so it would go to my http://mysite.com/421/salespage.php

What happened is now my affiliate sales page became a listing of the directory??

So I put it back until I figure this out, at least my affiliates traffic has a page that works, I need to figure this out so I can put another product on my CB account.

Here is the script in my root folder:

<?php


$default = "http://www.mystie.com/421/quit_smoking.php";


$page1 = "http://www.mysite.com/421/quit_smoking.php";
$page2 = "http://www.mysite.com/421/weightloss.php";



if ($_GET['pid']=='1')
header("Location: $page1");
else if ($_GET['pid']=='2')
header("Location: $page2");

else
header("Location: $default");
?>

Why is this defaulting to the .htm page??

Thanks,
Gary