Using filters and filter module

Hi Nicolas,
I'm having trouble using the filters and the filter module. I have set up the following filters:

FILTER
Find part (text, category = product category, including sub categories = yes, apply on = product_name and product_description)

JOOMLA MODULE
Hikashop filtering module (position: left, all menus, filters = Find part)

No matter what I type into the text box, all it does is display the filter module in the content area with no search results.

I tried to search for "laptop" on your demo site but it also returned nothing (not even the module in the content area) but there are products with laptop in the name.

Any ideas?

(Using Business 1.5.8 and Joomla 1.5.26)