We changed the software/script on my site.

The pages and links are different, we do still use the same id's, here is the real-world example:

Old script:

New script:

The only thing that is important here is the old "cat_id", which is now "aid", the number is the same (750 in this case) but since we're now using 4 digits, there needs to be an extra 0 for this, which I added. However, I can't get it to work...
I've placed this in the root (/) of my site.
The old script had 2 different pages, a details page and a categories page, both had the cat_id. The image_id from the details.php can be ignored, this can be redirected to the new album.php with the "aid".

Can anyone spot my fault(s) ?

PHP Code:
RewriteEngine On
^photos/categories\.php\?cat_id=([0-9]+)$ http://www.mysite.com/album.php?yr=2009&aid=0$1 

ThanQ Everyone !