I haven't tried this template on ZC v1,57 but it appears as though you have a partial page load - if you view the source of the page you can see, at the bottom, 'WARNING: An Error occurred, please refresh the page and try again.'

As a starting point, check out this link in Docs, https://docs.zen-cart.com/user/troub...ng/blank_page/, especially the 'Working with Debug Logs' section.