Dynamic Inlcude Question

[JGold1993]

Hi, I am new to this forum.

I have a question involving PHP dynamic includes, (I think). I am not the best at PHP, and I am surprised I have been able to run my website with PHP. But this is where I am..

http://killinginthename.com

My links go as follows:
http://killinginthename.com/?x=content/tutorials

but I want to make it so I can go:
http://killinginthename.com/?x=content/tutorials/photoshoptutorials/tutorial

or at least one more /filename

It doesn't seem to be working. Below is my PHP code:

<?php if (isset($_GET['x'])) {
   if (strpos($_GET['x'], "/")) {
      $dir = substr(str_replace('..', '', $_GET['x']), 0, strpos($_GET['x'], "/")) . "/";
      $file = substr(strrchr($_GET['x'], "/"), 1);
      if (file_exists($dir.$file.".php")) {
         include($dir.$file.".php");
      } else {
         include("default.php");
      }
   } else {
      if (file_exists(basename($_GET['x']).".php")) {
         include(basename($_GET['x']).".php");
      } else {
         include("default.php");
      }
   }
} else {
   include("default.php");
} ?>

Please help????