That's because you have categories showing on your main page set to true. Take a look at the code attached and upload it to your includes/templates/bookshelf/templates/tpl_index_categories.php. Since I believe your file might be customized, make sure to merge it (my file is commented, 6 new lines at the beginning). It should work after that.
<?php
/**
* Page Template
*
* Loaded by main_page=index<br />
* Displays category/sub-category listing<br />
* Uses tpl_index_category_row.php to render individual items
*
* @package templateSystem
* @copyright Copyright 2003-2006 Zen Cart Development Team
* @copyright Portions Copyright 2003 osCommerce
* @license http://www.zen-cart.com/license/2_0.txt GNU Public License V2.0
* @version $Id: tpl_index_categories.php 4678 2006-10-05 21:02:50Z ajeh $
*/
?>
<div class="centerColumn" id="indexCategories">
<!-- begin edit for ZX Slideshow -->
<?php
if(ZX_SLIDESHOW) { ?>
<?php require($template->get_template_dir('zx_slideshow.php',DIR_WS_TEMPLATE, $current_page_base,'templates'). '/zx_slideshow.php'); ?>
<?php } ?>
<!-- end edit for ZX Slideshow -->
<?php if ($show_welcome == true) { ?>
<h1 id="indexCategoriesHeading"><?php echo HEADING_TITLE; ?></h1>
<?php if (SHOW_CUSTOMER_GREETING == 1) { ?>
<h2 class="greeting"><?php echo zen_customer_greeting(); ?></h2>
<?php } ?>
<!-- deprecated - to use - uncomment
<?php if (TEXT_MAIN) { ?>
<div id="" class="content"><?php echo TEXT_MAIN; ?></div>
<?php } ?>-->
<!-- deprecated - to use - uncomment
<?php if (TEXT_INFORMATION) { ?>
<div id="" class="content"><?php echo TEXT_INFORMATION; ?></div>
<?php } ?>-->
<?php if (DEFINE_MAIN_PAGE_STATUS >= 1 and DEFINE_MAIN_PAGE_STATUS <= 2) { ?>
<div id="indexCategoriesMainContent" class="content"><?php
/**
* require the html_define for the index/categories page
*/
include($define_page);
?></div>
<?php } ?>
<?php } else { ?>
<h1 id="indexCategoriesHeading"><?php echo $breadcrumb->last(); ?></h1>
<?php } ?>
<?php
if (PRODUCT_LIST_CATEGORIES_IMAGE_STATUS_TOP == 'true') {
// categories_image
if ($categories_image = zen_get_categories_image($current_category_id)) {
?>
<div id="categoryImgListing" class="categoryImg"><?php echo zen_image(DIR_WS_IMAGES . $categories_image, '', SUBCATEGORY_IMAGE_TOP_WIDTH, SUBCATEGORY_IMAGE_TOP_HEIGHT); ?></div>
<?php
}
} // categories_image
?>
<?php
// categories_description
if ($current_categories_description != '') {
?>
<div id="categoryDescription" class="catDescContent"><?php echo $current_categories_description; ?></div>
<?php } // categories_description ?>
<!-- BOF: Display grid of available sub-categories, if any -->
<?php
if (PRODUCT_LIST_CATEGORY_ROW_STATUS == 0) {
// do nothing
} else {
// display subcategories
/**
* require the code to display the sub-categories-grid, if any exist
*/
require($template->get_template_dir('tpl_modules_category_row.php',DIR_WS_TEMPLATE, $current_page_base,'templates'). '/tpl_modules_category_row.php');
}
?>
<!-- EOF: Display grid of available sub-categories -->
<?php
$show_display_category = $db->Execute(SQL_SHOW_PRODUCT_INFO_CATEGORY);
while (!$show_display_category->EOF) {
// // echo 'I found ' . zen_get_module_directory(FILENAME_UPCOMING_PRODUCTS);
?>
<?php if ($show_display_category->fields['configuration_key'] == 'SHOW_PRODUCT_INFO_CATEGORY_FEATURED_PRODUCTS') { ?>
<?php
/**
* display the Featured Products Center Box
*/
?>
<?php require($template->get_template_dir('tpl_modules_featured_products.php',DIR_WS_TEMPLATE, $current_page_base,'templates'). '/tpl_modules_featured_products.php'); ?>
<?php } ?>
<?php if ($show_display_category->fields['configuration_key'] == 'SHOW_PRODUCT_INFO_CATEGORY_SPECIALS_PRODUCTS') { ?>
<?php
/**
* display the Special Products Center Box
*/
?>
<?php require($template->get_template_dir('tpl_modules_specials_default.php',DIR_WS_TEMPLATE, $current_page_base,'templates'). '/tpl_modules_specials_default.php'); ?>
<?php } ?>
<?php if ($show_display_category->fields['configuration_key'] == 'SHOW_PRODUCT_INFO_CATEGORY_NEW_PRODUCTS') { ?>
<?php
/**
* display the New Products Center Box
*/
?>
<?php require($template->get_template_dir('tpl_modules_whats_new.php',DIR_WS_TEMPLATE, $current_page_base,'templates'). '/tpl_modules_whats_new.php'); ?>
<?php } ?>
<?php if ($show_display_category->fields['configuration_key'] == 'SHOW_PRODUCT_INFO_CATEGORY_UPCOMING') { ?>
<?php include(DIR_WS_MODULES . zen_get_module_directory(FILENAME_UPCOMING_PRODUCTS)); ?><?php } ?>
<?php
$show_display_category->MoveNext();
} // !EOF
?>
</div>
