WHMCS WP Integration not working

Hi,
I've downloaded the WHMCS WP Integration, and i've installed it in a fresh installation of wordpress (with a Yootheme template with sample data), and the plugin is not working well.

The page with the [wcp_content] shortcode (http://plannerlab.com/dev/?page_id=674) load (although it takes a long time to load, it doesn't seems to be normal).

But when you click any link, it doesn't work, because the URL is weird (something like http://plannerlab.com/dev/?whmcsportal%5Bpage%5D=whmcs%3A%2F%2Fplannerlab.com%2Fgestion%2Fclientarea.php)

Help please. Thank you!