You don't need to rename the includes folder...the instructions are pretty clear:

Instructions for installation:

The files are arranged in the same structure as Zen Cart

These can all be uploaded via FTP to your server as they are without any editing required.

You can just FTP the whole /includes directories to your site.

Files included in package:

includes/languages/english/GinghamBlue/header.php
includes/templates/GinghamBlue/buttons/english/{all buttons}
includes/templates/GinghamBlue/common/tpl_footer.php
includes/templates/GinghamBlue/css/stylesheet.css
includes/templates/GinghamBlue/images/body_bg.jpg
includes/templates/GinghamBlue/images/logo.jpg
includes/templates/GinghamBlue/images/tile_back.jpg
includes/templates/GinghamBlue/copyright.txt
includes/templates/GinghamBlue/template_info.php
The above filenames are in the exact structure for where the files need to be placed, if you are following this then the template will show up in admin....I don't know why you would be renaming includes though when it doesn't say to do that?