I am trying a custom extension with table.i have create successfully but it load() function is not working..

Here total extension
config.xml path app/code/local/Amit/Productfaq/etc/

<?xml version="1.0"?>
<config>
    <modules>
        <Amit_Productfaq>
            <version>1.0.0</version>
        </Amit_Productfaq>
    </modules>
    <!-- Call Model -->
    <global>
        <models>
            <productfaq>
                <class>Amit_Productfaq_Model</class>
                <resourceModel>productfaq_resource</resourceModel>
            </productfaq>
            <productfaq_resource>
                <class>Amit_Productfaq_Model_Resource</class>
                <entities>
                    <productfaq>productfaq</productfaq>
                </entities>
            </productfaq_resource>
        </models>
        <resources>
            <productfaq_setup>
                <setup>
                    <module>Amit_Productfaq</module>
                </setup>
                <connection>
                    <use>core_setup</use>
                </connection>
            </productfaq_setup>
            <productfaq_read>
                <connection>
                    <use>core_read</use>
                </connection>
            </productfaq_read>
            <productfaq_write>
                <connection>
                    <use>core_write</use>
                </connection>
            </productfaq_write>
        </resources>
        <!-- helper -->
        <helpers>
            <productfaq>
                <class>Amit_Productfaq_Helper</class>
            </productfaq>
        </helpers>
    </global>
    <frontend>
        <routers>
            <productfaq>
                <use>standard</use>
                    <args>
                        <module>Amit_Productfaq</module>
                        <frontName>productfaq</frontName>
                    </args>
            </productfaq>
        </routers>
    </frontend>
</config>

Model file are
Productfaq.php path app/code/local/Amit/Productfaq/Model

<?php
class Amit_Productfaq_Model_Productfaq extends Mage_Core_Model_Abstract
{
    public function _construct()
    {
        $this->_init('productfaq/productfaq');
    }
    public function abc(){
    return "amit";
    }

}

Productfaq.php app/code/local/Amit/Productfaq/Model/Resource/

<?php
class Amit_Productfaq_Model_Productfaq_Resource_Productfaq extends Mage_Core_Model_Resource_Db_Abstract
{
    protected function _construct()
    {
        $this->_init('productfaq/productfaq', 'productfaq_id');
    }
}

installer install.php \app\code\local\Amit\Productfaq\sql\productfaq_setup

<?php
$installer=$this;
$installer->startSetup();

$installer->run("
-- DROP TABLE IF EXISTS {$this->getTable('productfaq')};
CREATE TABLE {$this->getTable('productfaq')} (
  `productfaq_id` int(11) unsigned NOT NULL auto_increment COMMENT 'Q&A ID',
  `product_id` int(11) NOT NULL  COMMENT 'Product Id' ,
  `customer_name` varchar(255) NOT NULL COMMENT 'Customer Name',
  `customer_email` varchar(255) NOT NULL  COMMENT 'Customer Email',
  `question` text NOT NULL  COMMENT 'Question',
  `answer` text NOT NULL  COMMENT 'Answer',
  `status` smallint(6) NOT NULL default '0' COMMENT 'Status',
  `created_time` datetime NULL,
  `update_time` datetime NULL,
  PRIMARY KEY (`productfaq_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

    ");
$installer->endSetup();
?>

Module file Amit_Productfaq.xml path is app/etc/modules/

<?xml version="1.0"?>
<config>
    <modules>
        <Amit_Productfaq>
            <codePool>local</codePool>
            <active>true</active>
        </Amit_Productfaq>
    </modules>
</config>

Mage::getModel('productfaq/productfaq')->load(1)
Show the error "Fatal error: Call to a member function load() on a non-object in C:\wamp\www\magento1702v1\app\code\local\Mage\Core\Model\Abstract.php on line 225".

I have insert the data in table

INSERT INTO `productfaq` (`productfaq_id`, `product_id`, `customer_name`, `customer_email`, `question`, `answer`, `status`, `created_time`, `update_time`) VALUES
(1, 45, 'Amit Bera', 'amit@gmail.com', 'I love you ', 'Mage_Core_Controller_Front_Action', 1, '2014-03-25 00:00:00', '2014-03-31 00:00:00');