To be honest I'm not sure, but the following should help.
A quick solution would be to edit index.php file and change 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>');
But only change the text I have displayed in Italic. Leave the rest as is.
Something else to check, is that your template is installed correctly into zen cart and it is set as the default template.
Goto > Tools > Template Section
Click on the Default(All) line, and then select Edit. Now select your template name from the drop down list and click on Update.
Repeat this for English as well.
Should end up looking like this:-

Hope that helps.
Personaly I'm writting my own ecommerce system now. Had a nightmare with Zen Cart, a real learning curve. I'm not dismissing it out of hand as its great for low cost (as in non) but I could build something quicker (as in functioning), and cleaner in php.