PHP: Fatal error: Call to a member function on a non-object

Getting a very strange error here, I am writing a flatfile database class and this was all working fine until I refreshed and now I am constantly getting this message:

Fatal error: Call to a member function name() on a non-object in /home/reithg/public_html/test/engine/class.database.php on line 50

I am calling the Class as follows:

<?php
ini_set('display_errors', '1');

require('engine/class.database.php');

$config = new Config("lessons", array('first', 'second', 'third', 'fourth'), "data/");
$db = new Database($config, true);

print("Querying DB for 'theta' no exclusions: <br />");
print_r($db->query('theta', NULL, NULL));

print("<p /> Querying DB for 'theta' in column 'second': <br />");
print_r($db->query('theta', 'second', NULL));

print("<p /> Querying DB for first two rows: <br />");
print_r($db->getRows(2));

print("<p /> Querying DB for last three rows: <br />");
print_r($db->getRows(3, true));

print("<p /> Cleaning data for safe DB input: <br />");
$testInput = array('escape|these||delimiters','and\these\\slashes','and\0these\0nulls',"don't, forget quotes");
print("input: ");
print_r($testInput);
echo("<br />output: ");
print($db->addRow($testInput));
?>

Here is my class.database.php

<?php
require('class.config.php');
require('class.column.php');

    class Database {
        private
            $_config,
            $_pointer;

        public function __construct(Config $config)  {
            $this->_config = $config;
            return true;
        }

        private function connect($method) {
            if (!($this->_pointer = @fopen($this->_config->db(), $method)))
            echo("Unable to connect to database");
        }

        private function disconnect() {
            fclose($t