R/W files outside the WebServer folder

I'm sure this is an easy one, but I can't create or access anything outside my "/Library/WebServer/" folder from PHP. I read the permissions documentation but it hasn't helped, Could someone explain how to do the following? I created the folder "/users/testuser/desktop/test_folder" on my Mac desktop, chmoded it to 0777 and want the ability to create both files and folders inside this folder. Here's a little script I wrote to work out the details <?PHP $base_dir = "/users/testuser/desktop/test_folder"; $new_dir = mkdir($base_dir."/05.08.2003", 0777); ?> When run from a browser, I get the following error: Warning: mkdir(/users/testuser/desktop/test_folder/05.08.2003) [function.mkdir]: No such file or directory in /Library/WebServer/Documents/junk.php on line 2 Clearly permissions are the problem but I don't know how to give PHP the permissions it wants. Could someone show me step by step how to do it? Thanks, Ken Tozier