Which template is loaded when category has no products?

I'm working on my first OpenCart site:
http://golike.com/burklund/store

So far I've been pretty successful at skinning my design to the OpenCart template system. I've figured out which .tpl files to modify in:
/catalog/template/mytemplate/content
/catalog/template/mytemplate/module

The category.tpl in the content folder seems to be the one loaded when you navigate click on a category to view its products. For example:
http://golike.com/burklund/store/index. ... ry&path=23

But when I try a category that doesn't have any products in it:
http://golike.com/burklund/store/index. ... ry&path=26

The header and sidebar looks fine, which tells me it's loading the layout.tpl and all of the tpl's in the module folder, but the main content section doesn't look right. Examining the source tells me it's loading template code other than content/category.tpl.

Anyone know which .tpl file gets loaded when you view an empty category?

content/error.tpl

Excellent, that did the trick Bruce. Thanks.