Grid layout to product listing

Hello world!
This is my first post here so I'm new here. I have been struggling for some time with Zen Cart and I have one problem I can't get over. I'm building e-commerce here and I would like to use front pages grid layout (under "tammikuun uutuudet") in product listing pages (for example "Kalusteet" -category). Now you can see products as list. I would like to see them in grid layout. How can I do this? Template I'm using is Apparel Boutique and Zen Cart version is v1.50.

You need a mod for that:

http://www.zen-cart.com/index.php?main_page=product_contrib_info&products_id=77

I tried install this mod and run SQL commands on database but I got message "WARNING: An Error occurred, please refresh the page and try again."

https://www.zen-cart.com/tutorials/index.php?article=412

[15-Jan-2012 15:55:46] PHP Fatal error: 1062:Duplicate entry 'PRODUCT_LISTING_LAYOUT_STYLE' for key 'unq_config_key_zen' :: INSERT INTO configuration (configuration_title, configuration_key, configuration_value, configuration_description, configuration_group_id, sort_order, last_modified, date_added, use_function, set_function) VALUES ('Product Listing - Layout Style', 'PRODUCT_LISTING_LAYOUT_STYLE', 'rows', 'Select the layout style:<br />Each product can be listed in its own row (rows option) or products can be listed in multiple columns per row (columns option)', '8', '40', NULL, now(), NULL, 'zen_cfg_select_option(array("rows", "columns"),'); in /home/succe251/public_html/zen-cart/includes/classes/db/mysql/query_factory.php on line 101

I can't understand this. Please some body help me?!

Edit: This is my site's myDebug-xxxxxxx.log

Thank you stevesh! I got it work :) I forgot to configurate Admin > Configuration > Product Listing > Product Listing - Layout Style to Columns.