I have filed 'read' in alireza_checkingout_checkingout table I want to add condition if read =0 in query below, I alreadt tried ->addFieldToFilter( 'read', array('eq' => 0)) but the system return erro "tal error: Call to a member function getBackend() on boolean in /var/www/html/megadump/app/code/core/Mage/Eav/Model/Entity/Abstract.php on line 816"

            $collection = Mage::getResourceModel('customer/customer_collection')

            ->addNameToSelect()
            ->addAttributeToSelect('email')
            ->addAttributeToSelect('created_at')
            ->addAttributeToSelect('group_id')
            ->joinTable('alireza_checkingout_checkingout','alireza_customer_id=entity_id',array('alireza_customer_id','read'),null,'left')
            ->joinAttribute('billing_postcode', 'customer_address/postcode', 'default_billing', null, 'left')
            ->joinAttribute('billing_city', 'customer_address/city', 'default_billing', null, 'left')
            ->joinAttribute('billing_telephone', 'customer_address/telephone', 'default_billing', null, 'left')
            ->joinAttribute('billing_region', 'customer_address/region', 'default_billing', null, 'left')
            ->joinAttribute('billing_country_id', 'customer_address/country_id', 'default_billing', null, 'left');
            $collection->getSelect()->columns('count(alireza_customer_id) as cc')->group('entity_id');
        $this->setCollection($collection);

        return Mage_Adminhtml_Block_Widget_Grid::_prepareCollection();

I have filed 'read' in alireza_checkingout_checkingout table I want to add condition if read =0 in query below, I alreadt tried ->addFieldToFilter('read', array('eq' => 0)) but the system return an error "fatal error: Call to a member function getBackend() on boolean in /var/www/html/megadump/app/code/core/Mage/Eav/Model/Entity/Abstract.php on line 816"

$collection = Mage::getResourceModel('customer/customer_collection')

 ->addNameToSelect()
 ->addAttributeToSelect('email')
 ->addAttributeToSelect('created_at')
 ->addAttributeToSelect('group_id')
 ->joinTable('alireza_checkingout_checkingout','alireza_customer_id=entity_id',array('alireza_customer_id','read'),null,'left')
 ->joinAttribute('billing_postcode', 'customer_address/postcode', 'default_billing', null, 'left')
 ->joinAttribute('billing_city', 'customer_address/city', 'default_billing', null, 'left')
 ->joinAttribute('billing_telephone', 'customer_address/telephone', 'default_billing', null, 'left')
 ->joinAttribute('billing_region', 'customer_address/region', 'default_billing', null, 'left')
 ->joinAttribute('billing_country_id', 'customer_address/country_id', 'default_billing', null, 'left');
 $collection->getSelect()->columns('count(alireza_customer_id) as cc')->group('entity_id');
 $this->setCollection($collection);

 return Mage_Adminhtml_Block_Widget_Grid::_prepareCollection();