In that case try using my first option, and edit the file called /includes/languages/english/index.php
The includes directory is in the root of your web space.
You see my site (https://www.themobilephonesite.co.uk) works differntly to yours. On the site I developed the template shows products in the middle field, by-passing Zen Carts default index page.
It appears (without being able to look at your file structure) that your template doesn't work in the same way.
If you edit that file above as I mentioned in my first post, it may solve the problem.
Open it in Notepad (in Windows it's what I always use, or you could download Komodo Edit).
Open that file and edit the following line:-
define('TEXT_MAIN','This is the main define statement for the page for english when no template defined file exists. It is located in: <strong>/includes/languages/english/index.php</strong>');
So it looks something like this:-
define('TEXT_MAIN','Hi and welcome to the Poser Underground online store!');
Then save it, and upload. Always backup the old file just incase something goes wrong.
Matt