creating upload folder every day?

hello,
I want to create new folder every day and upload to it.
Example:
on 23-6-2009 a folder named 23-6-2009 will be create under userfiles:(so the result will be (userfiles/23-6-2009/).

I add the following to config.php

$Config['UserFilesPath'] = '/userfiles/'.date("Y-m-d").'/' ;


   $filename =$Config['UserFilesPath'];

   
    if (file_exists($filename)) {  

    } else {  
        mkdir( $filename, 0777);  
    }  

It works fine with windows but when I upload it to my server (centOS) it did not work. I have enabled and disbaled the safe mode and the result the same. (it only create the folder 23-9-2009 but can not put the uploaded files inside it)



thanks for help.