Zip downloads only images?

Gallery version (not just "2"): 2
PHP version (e.g. 5.1.6): 5
PHPInfo Link (see FAQ):
Webserver (e.g. Apache 1.3.33): Windows IIS 6.0
Database (e.g. MySql 5.0.32): mySQL
Activated toolkits (e.g. NetPbm, GD): GD, Zip
Operating system (e.g. Linux): Windows
Browser (e.g. Firefox 2.0): FireFox 3

I have enabled and got the zip cart feature working. The problem is it only works on

Root > Album main > sub albums > sub album > images (if your press add to cart it works here)

.. basically it only adds single images .. I want it to download and create zip everytime someone press download album...

Try it yourself.. http://tinyurl.com/39vgcus it will just keep saying your cart is empty unless you add a product single image

Thanks