repair links in sitepro shopping cart

The links in my shopping cart stopped working and need to be replaced. This should be a very quick and easy fix. Everything else has been check and is working correctly but the links result in a 404 error page. The website is [login to view URL] The links are under the catalog section. There are pictures that you click on that should take you to the product. They don't work any more. I want to know why they are not working and have them fixed.