my Custom code is throwing an error

[tcarden]

i hope this isn't asking too much, but what is wrong w/ my PHP?, it is throwing an error. i've added this to the tpl_index_product_list.php

$catId = substr($_GET['cPath'], 0, 1); //Returns a single INT, a categorie_id

// this SQL statement reads correctly i'm pretty sure
$sql = 'select * from categories_description where categorie_id = '. $catId;

//this throws an error
$cat_info = $db->Execute($sql);

i really appreciate all the help i've gotten on this Forum!