No result when using {exp:freebie:category_id segment='4'} in a channel entries tag

[lkdennis]

I know freebie is set up as it returns the category ID and category name outside the channel entries tag. If i substitue an actual category number for the {exp:freebie:category_id segment='4'} I get the list of products in that category.

My code:

Products in Category {exp:freebie:category_id segment='4'}-{exp:freebie:category_name segment='4'}

  <ul>
{exp:channel:entries channel="lumber_products" category="{exp:freebie:category_id segment='4'}" parse="inward"}
<li><a href="{path='lumber/products'}/{freebie_4}/{category_url_title}/{url_title}">{title}</a></li>
     {/exp:channel:entries}
  </ul>

This returns
Products in Category 2-Industrial Commercial and Agricultural
and then a blank page.

I am new to structure and freebie, but have several EE2 sites.