fatal error: PHP? why

[grock]

Can someone tell me why I am getting this error on my initial shopping cart index page (the "welcome guest" page.)

Fatal error: main(): Failed opening required '' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/account.../public_html/shopcart/includes/templates/template_custom/templates/tpl_index_default.php on line 42

thanks. this is my first post. glad to find a zencart community.
-G

[Kim]

Sounds like some missing or corrupted files. FTP all of the files and see if that doesn't fix it.