datatables error with search box only using pdo format

Question

Managed to get PDO style working with DataTables and everything works fine, BUT the search box functionality. Display, paging, column sorting, etc all works, but as soon as I try to use the search box I get this error retrieved from firebug :

<br />
<b>Fatal error</b>:  Uncaught exception 'PDOException' with message 'SQLSTATE[HY093]: Invalid parameter number' in /home/test/public_html/assets/data-tables/test-pdo.php:94
Stack trace:
#0 /home/test/public_html/assets/data-tables/test-pdo.php(94): PDOStatement-&gt;execute()
#1 /home/test/public_html/assets/data-tables/test-pdo.php(140): TableData-&gt;get('accounts', 'account_id', Array)
#2 {main}
thrown in <b>/home/test/public_html/assets/data-tables/test-pdo.php</b> on line <b>94</b><br />

Any ideas with this?

<?php

/*
 * Script:    DataTables server-side script for PHP and MySQL
 * Copyright: 2012 - John Becker, Beckersoft, Inc.
 * Copyright: 2010 - Allan Jardine
 * License:   GPL v2 or BSD (3-point)
 */

define('INCLUDE_CHECK',true);

// These files can be included only if INCLUDE_CHECK is defined
require '/home/test/public_html/assets/functions/connect.php';

//inject bd connection into class
class TableData {
    /** @var \PDO */
    protected $_db;

    public function __construct(\PDO $_db) {
         $this->_db = $_db;
    }

    public function get($table, $index_column, $columns) {

        // Paging
        $sLimit = "";
        if ( isset( $_GET['iDisplayStart'] ) && $_GET['iDisplayLength'] != '-1' ) {
            $sLimit = "LIMIT ".intval( $_GET['iDisplayStart'] ).", ".intval( $_GET['iDisplayLength'] );
        }

        // Ordering
        $sOrder = "";
        if ( isset( $_GET['iSortCol_0'] ) ) {
            $sOrder = "ORDER BY  ";
            for ( $i=0 ; $i<intval( $_GET['iSortingCols'] ) ; $i++ ) {
                if ( $_GET[ 'bSortable_'.intval($_GET['iSortCol_'.$i]) ] == "true" ) {
                    $sortDir = (strcasecmp($_GET['sSortDir_'.$i], 'ASC') == 0) ? 'ASC' : 'DESC';
                    $sOrder .= "`".$columns[ intval( $_GET['iSortCol_'.$i] ) ]."` ". $sortDir .", ";
                }
            }

            $sOrder = substr_replace( $sOrder, "", -2 );
            if ( $sOrder == "ORDER BY" ) {
                $sOrder = "";
            }
        }

        /* 
         * Filtering
         * NOTE this does not match the built-in DataTables filtering which does it
         * word by word on any field. It's possible to do here, but concerned about efficiency
         * on very large tables, and MySQL's regex functionality is very limited
         */
        $sWhere = "";
        if ( isset($_GET['sSearch']) && $_GET['sSearch'] != "" ) {
            $sWhere = "WHERE (";
            for ( $i=0 ; $i<count($columns) ; $i++ ) {
                if ( isset($_GET['bSearchable_'.$i]) && $_GET['bSearchable_'.$i] == "true" ) {
                    $sWhere .= "`".$columns[$i]."` LIKE :search OR ";
                }
            }
            $sWhere = substr_replace( $sWhere, "", -3 );
            $sWhere .= ')';
        }

        // Individual column filtering
        for ( $i=0 ; $i<count($columns) ; $i++ ) {
            if ( isset($_GET['bSearchable_'.$i]) && $_GET['bSearchable_'.$i] == "true" && $_GET['sSearch_'.$i] != '' ) {
                if ( $sWhere == "" ) {
                    $sWhere = "WHERE ";
                }
                else {
                    $sWhere .= " AND ";
                }
                $sWhere .= "`".$columns[$i]."` LIKE :search".$i." ";
            }
        }

        // SQL queries get data to display
        $sQuery = "SELECT SQL_CALC_FOUND_ROWS `".str_replace(" , ", " ", implode("`, `", $columns))."` FROM `".$table."` ".$sWhere." ".$sOrder." ".$sLimit;
        $statement = $this->_db->prepare($sQuery);

        // Bind parameters
        if ( isset($_GET['sSearch']) && $_GET['sSearch'] != "" ) {
            $statement->bindValue(':search', '%'.$_GET['sSearch'].'%', PDO::PARAM_STR);
        }
        for ( $i=0 ; $i<count($columns) ; $i++ ) {
            if ( isset($_GET['bSearchable_'.$i]) && $_GET['bSearchable_'.$i] == "true" && $_GET['sSearch_'.$i] != '' ) {
                $statement->bindValue(':search'.$i, '%'.$_GET['sSearch_'.$i].'%', PDO::PARAM_STR);
            }
        }

        $statement->execute();
        $rResult = $statement->fetchAll();

        $iFilteredTotal = current($this->_db->query('SELECT FOUND_ROWS()')->fetch());

        // Get total number of rows in table
        $sQuery = "SELECT COUNT(`".$index_column."`) FROM `".$table."`";
        $iTotal = current($this->_db->query($sQuery)->fetch());

        // Output
        $output = array(
            "sEcho" => intval($_GET['sEcho']),
            "iTotalRecords" => $iTotal,
            "iTotalDisplayRecords" => $iFilteredTotal,
            "aaData" => array()
        );

        // Return array of values
        foreach($rResult as $aRow) {
            $row = array();         
            for ( $i = 0; $i < count($columns); $i++ ) {
                if ( $columns[$i] == "version" ) {
                    // Special output formatting for 'version' column
                    $row[] = ($aRow[ $columns[$i] ]=="0") ? '-' : $aRow[ $columns[$i] ];
                }
                else if ( $columns[$i] != ' ' ) {
                    $row[] = $aRow[ $columns[$i] ];
                }
            }
            $output['aaData'][] = $row;
        }

        echo json_encode( $output );
    }

}

header('Pragma: no-cache');
header('Cache-Control: no-store, no-cache, must-revalidate');

// Create instance of TableData class
//$table_data = new TableData();
$table_data = new TableData($db);

// Get the data
//$table_data->get('table_name', 'index_column', array('column1', 'column2', 'columnN'));
$table_data->get('accounts', 'account_id', array('account_id', 'account_username', 'account_password', 'account_email'));

?>