Your link should look more like this:

<a href="<?php echo zen_href_link('accounting_tool', 'order=order_total&sort=' . ($_GET['sort'] == 'desc' ? 'asc' : 'desc')); ?>">LINK TEXT</a>

The coding will handle the .php extension, and the parameters should go in the second variable, rather than sending the whole URL in the first variable. Finally, you can leave out the NONSSL, as this is the default set within the function, and if left blank, will automatically default to a non-secure page.

Hope this helps,

Absolute