Custom drupal form with table select and paging

drupal-form.php

<?php

function referrals_search_cardlist2() {
  global $user;
	$output = drupal_render(drupal_get_form('referrals_form_listpin'));
	return $output;
}

function referrals_form_listpin()
{
  // set limit for pager
	$limit = 50;
	// define table header
	$header = array(
		array('data' => t('ID'), 'field'=>'id', 'sort'=>'asc'),
		array('data' => t('Program')),
		array('data' => t('Serial'),    'field'=>'serial'),
		array('data' => t('PIN'),    'field'=>'pinnumber'),
		array('data' => t('Status'), 'field'=>'status'),
		array('data' => t('Aktifasi'), 'field'=>'activated'),
		array('data' => t('Member'), 'field'=>'activated'),
	);
	# set the database table and initial SelectQuery options
	# $select is a SelectQuery object.
	# @see http://api.drupal.org/api/drupal/includes--database--select.inc/class/Se...
	$select = db_select('referrals_cardlist', 'rc')
		->extend('PagerDefault')
		->extend('TableSort');
	# get the desired fields
	# orderByHeader is a TableSort method (http://api.drupal.org/api/drupal/includes--tablesort.inc/function/TableS...)
	$select->condition('program',$status,'=')
		->condition('upgrade',($upgrade?'1':'0'),'=')
		->fields('rc')
		->orderByHeader($header)
		->limit($limit);
	# execute the query
	$results = $select->execute();

	// build options
	$options = array();
	while($item = $results->fetchObject()) {
		// each element of the array is keyed with the serial number
		if (isset($item->uid))
			$member=user_load($item->uid);
		$options[$item->serial] = array( 
			0 => $item->id,
			1 => $item->program,
			2 => $item->serial,
			3 => $item->pinnumber, 
			4 => ($item->status ? "Aktif" : "Pasif"),
			5 => !isset($item->activated) ? '' : format_date($item->activated,'custom','d F Y H:i'),
			6 => !isset($item->uid) ? '' : $member->name,
		);
		if (isset($member)) 
			unset($member);
	}

	$form = array();
	$form['table'] = array(
		'#type'=>'tableselect',
		'#header' => $header,
		'#options' => $options,
		'#multiple' => TRUE,
		'#weight' => 10,
	);
	$form['pager'] = array(
		'#markup' => theme('pager'),
		'#weight' => 12,
	);
	$form['activate'] = array(
		'#type'=>'submit',
		'#value' => t('Aktif'),
		'#weight' => 15,
	);
	$form['deactivate'] = array(
		'#type'=>'submit',
		'#value' => t('Pasif'),
		'#weight' => 15,
	);

	return $form;
}