Newbie error no doubt

[cspgsl]

Can somone tell me what this error means

Fatal error: main(): Failed opening required '' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/pencils/public_html/cart/includes/templates/bsd/templates/tpl_gallery_default.php on line 37

Looking at line 37 isn't telling me anything as it looks like it's supposed to look.

Thanks

[cspgsl]

Here is the page that the error refers to:

?>
<table  width="100%" border="0" cellspacing="2" cellpadding="2">
  <tr>
    <td class="breadCrumb"><?php echo $breadcrumb->trail(BREAD_CRUMBS_SEPARATOR); ?></td>
  </tr>
  <tr>
    <td class="pageHeading" align="center"><h1><?php echo HEADING_TITLE; ?></h1></td>
  </tr>
<?php if (TEXT_INFORMATION) { ?>
  <tr>
    <td class="main"><?php echo TEXT_INFORMATION; ?></td>
  </tr>
<?php } ?>
<?php if (DEFINE_GALLERY_STATUS == '1') { ?>
  <tr>
    <td class="plainBox"><?php require($define_gallery); ?></td>
  </tr>
<?php } ?>
  <tr>
    <td class="main"><?php echo zen_back_link() . zen_image_button(BUTTON_IMAGE_BACK, BUTTON_BACK_ALT) . '</a>'; ?></td>
  </tr>
</table>

[Houdini]

The script is not finding the include file, it could be a typo or improper path, but the file you are requiring is not where it is in the call to it.

[laserlight]

What is $define_gallery?