php halfway working

I have recently installed Apache 1.3.28 on Windows XP with PHP 4.3.3 (both manual install and automatic .exe install) and MySQL 3.23.49. I have a script

<?php

if (! file_exists("$x.php"))

{

include("news/news.php");

}

else

{

include("$x.php");

}

?>

that code lets me do this as my url
"http://whatever.com/index.php?x=page"
I know this works, because I have hosting (not on my computer) and it works fine, but I cant get it to work on my computer. Is there any options that need to be set? or any "extensions" that I keep reading about in the manual install "INSTALL" file. I am completly new to running a server on my computer and I only want it there so I can test any scripts I make. It gets tiring uploading stuff every other second when I make a change. Thanks for any help!
Andrew

[barand]

You need to specify 'includes' path in your php ini file and put included files there.