BleepingComputer.com: PHP file upload problem

Hi,
I wanted to make an admin page on my site so I can upload images using web admin interface and so that I don't have to go through FTP upload. Here is my stripped down code for uploading :

<form enctype="multipart/form-data" action="index.php" method="post">
<input type="hidden" name="MAX_FILE_SIZE" value="100000" />
Upload : <input name="picture" type="file" /><br />
<input type="submit" value="Upload" />
</form>

But the thing is that it does not work when I click Upload button. The $_POST and $_FILES variables are empty. I checked by using print_r($_POST) and print_r($_FILES). The result is that it prints only Array()

I Googled and found many people facing this problem but could not find any solution. I tested on WAMP on Windows Vista, then tested on Ubuntu but nothing works.

Please suggest me some solutions or other methods of uploading a file through web interface.
Thanks.

What is the name of the file that is supposed to be getting the image? Is it really index.php?

Yes. I was testing on local server with that file name. I would change it to something else when uploading to actual web host.

Without seeing all of our code, I can't say for sure. My forms for file uploads are just like that, except I am using AJAX to do the uploads. All I could guess is that you have a syntax error somewhere.

EDIT: I lied (well, sort of). I am using the same form, but I am using a control from the YUI library that is handling the actual upload.

Thanks groovicus for hinting at YUI library, its amazing