Hello, we just upgraded our Zen Cart and are now getting this error on the shop's home page:

Fatal error: main() [function.require]: Failed opening required '' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/user/public_html/shop/includes/templates/seasidekites/templates/tpl_index_default.php on line 33

We dearly need some assistance with solving this quickly, any help would be greatly appreciated.