Getting errors when linking to the product listing page

Just setting everything up, and I can't seem to figure out how to view the product listing page without getting errors. Here is the link in question: http://bogusnetwork.com/clients/?whmcsportal%5Bpage%5D=whmcs%3A%2F%2Fbogusnetwork.com%2Fbilling%2Fcart.php

Any ideas?